Nutrients

Understanding Fertilizer Material

Understanding Fertilizer Material

There is great variety among fertilizer materials. In general, fertilizers fall within two major categories: commercial fertilizer sources and organic sources. While it is difficult to make direct comparisons between these two sources, a few loose comparisons can be made.

First, commercial sources are typically high analysis fertilizers, while organic sources are low analysis. This means that commercial fertilizers contain a larger percentage of a given nutrient than organic sources. As a result, commercial fertilizers are applied in lesser amounts than organic sources, since it take less commercial fertilizers to achieve a given rate.

Secondly, composition of organic fertilizer is generally much more varied than commercial fertilizers. This lack of consistency can make it difficult to predict how much organic fertilizers should be applied in order to obtain a desired rate.

Thirdly, commercial fertilizer production is fossil fuel intensive. As a result, the price of commercial fertilizer can be relatively expensive.

Commercial fertilizer sources

NITROGEN FERTILIZERS

Anhydrous ammonium is the starting block for most inorganic nitrogen fertilizers. Anhydrous ammonium is manufactured by reacting N2 with H2 under extreme heat and pressure in the presence of a catalyst, known as the Haber-Bosch technology. The Haber-Bosch technology requires large energy input, but allows for the manufacture of high N analysis fertilizers.

Anhydrous Ammonium

  • Anhydrous ammonium has the highest nitrogen analysis out of all inorganic fertilizers
  • It is comprised of 82% nitrogen.
  • It must be kept under pressure since it evaporates under normal atmospheric pressure.
  • It is very harmful to human tissue, such as eyes, skin, and lungs. Thus, there are many safety precautions associated with the handling of NH3.

Ammonium sulfate

  • Contains 21% nitrogen and 11% sulfur
  • Sugarcane and pineapple production
  • Ammonium sulfate is acid forming and lowers soil pH.

Ammonium phosphate

Monoammonium phosphate (MAP)

  • 11-18% nitrogen and 48-55% P2O5
  • MAP is a water soluble fertilizer
  • The soil pH temporarily lowers to about 3.5 in areas where MAP initially reacts with soil.

Diammonium phosphate (DAP)

  • 18-21% nitrogen and 46-53% P2O5
  • DAP is a water soluble fertilizer.
  • The soil pH temporarily reduces to 8.5 in areas where DAP initially reacts with soil.
  • DAP may produce free ammonia in high pH soils, which may cause seed injury if placed too close to seed rows.

Potassium nitrate

  • 13% nitrogen and 44% K2O
  • Provides soil with readily available nitrate, which generally increases soil pH.

Calcium nitrate

  • 15% nitrogen and 34% CaO
  • Provides soil with readily available nitrate.
  • However, calcium nitrate is hygroscopic (absorbs moisture from air) and must be kept under air-tight storage conditions.

Urea

  • 45-46% nitrogen
  • Advantages of urea over other nitrogen sources include:
    • reduced caking of fertilizer material
    • less corrosion on equipment
    • decreased costs associated with storage, transportation, and handling
  • Once applied to the soil, an enzyme known as urease transforms urea to NH4+ and HCO3-.
    • This transformation readily occurs under warm, moist conditions.
  • Urea temporarily increases the pH of the soil it contacts, due to the initial release of NH3. However, the soil pH may ultimately decrease as the NH4+ nitrifies to NO3-, which is an acid producing reaction.
  • In soils with high pH, NH4+ may volatilize and escape from the soil in the form of NH3. Volatilization losses are reduced by incorporating or washing urea into the soil.
  • Urea can contain biurate, which is phytotoxic to most plants.
    • Although most plants tolerate up to 2% biurate levels, pineapple and citrus are sensitive to biuret. The urea should contain less than 0.25% biuret.

Sulfur-coated urea

  • 22-38% nitrogen and 12-22% sulfur
  • Sulfur-coated urea is a controlled release fertilizer.
    • It contains a coat of sulfur that surrounds a urea granule, which controls its release.
    • Urea is only released after the sulfur coat is oxidized by microorganisms.
    • The rate at which urea becomes available depends on the thickness of the sulfur coat.
  • Sulfur coated urea is advantageous in coarse textured soils and/or soils that have a great nitrate leaching potential.

PHOSPHATE

The major source of inorganic phosphorus fertilizers is rock phosphate. Rock phosphate is a naturally occurring mineral, which is mined from the earth. Deposits of rock phosphate occur around the world, such as in the United States, Russia, Morocco, and China.

Rock phosphate (RP)

  • 27-41% P2O5 and 25% Calcium
  • The minerals that make up RP are various forms of apatite. The reactivity of RP depends on the type of apatite and its inherent purity. RP is not water soluble and only becomes available to plants under acidic conditions. RP is most reactive when it is finely ground and incorporated into warm, moist, acidic soils with long growing seasons. Although the availability of RP is slow, it has a great long term residual effect.

Superphosphate

Single superphosphate (SSP)

  • 16-22% P2O5, 11-12% sulfur, and 20% calcium
  • SSP is manufactured by reacting RP with sulfuric acid.
  • SSP does not have a great influence on soil pH.

Triple superphosphate (TSP)

  • 44-52% P2O5, 1-1.5% sulfur, and 13% Ca
  • TSP is produced by treating RP with phosphoric acid
  • Like SSP, TSP does not have a great effect on soil pH.

Ammonium phosphate

Monoammonium phosphate (MAP)

  • 11-13% N, 48-62% P2O5, and 0-2% S
  • MAP is water soluble.
  • MAP temporarily lowers the soil pH to 3.5 in areas where MAP initially reacts with the soil.

Diammonium phosphate (DAP)

  • 18-21% N, 46-53% P2O5, and 0-2% S
  • DAP are water soluble.
  • The soil pH temporarily lowers to 8.5 in areas where DAP initially reacts.
  • DAP may produce free NH3 in soils with a high pH, which may cause seed injury if placed close to seed rows.

POTASSIUM

Potassium is mined from the earth as soluble potassium salts, or potash, with varying degree of purity. Canada is home to the world’s largest potash deposit.

Potassium chloride (muiate of potash)

  • 60-63% K2O
  • KCl is the most commonly used K fertilizer.
  • KCl readily dissolves in water

Potassium sulfate (sulfate of potash)

  • 50-53% K2O, 17% S K2SO4-
  • Potassium sulfate is completely water soluble.
  • In comparison to KCl, potassium sulfate:
    • has a lower salt index
    • may be used on crops that are sensitive to Cl- (i.e. avocado).

Potassium nitrate

  • 44% K2O and 13% N
  • Potassium nitrate is also water soluble.
  • Increases soil pH
  • Potassium nitrate is also a source of nitrogen.

Potassium-magnesium sulfate

  • 22% K2O, 11% Mg, and 22% S
  • This inorganic fertilizer does not have a significant effect on soil pH

CALCIUM

Lime

  • Soil amendment which is commonly used to raise the pH of the soil.
  • Ground coral in Hawaii contains 38% Mg and 0.6% Mg

Calcium Carbonate

  • Approximately 38% Ca, depending upon its source
  • A common liming material, calcium carbonate also supplies calcium to the soil.

Dolomite

  • 22% Ca and 12% Mg, depending upon the dolomite source
  • In addition to raising the pH, dolomite is a source of calcium and magnesium.

Gypsum

  • 23% Ca and 19% S
  • Unlike liming materials, gypsum does not increase the soil pH.
  • In addition to providing calcium and sulfur, gypsum may be used to correct soil physical problems and/or aluminum toxicities.

Calcium nitrate

  • 15% N and 20% Ca
  • Calcium nitrate is very soluble in water.

Superphosphates

Single (SSP)

  • 18-21% Ca
  • SSP supplies both calcium and phosphate.

Triple (TSP)

  • 12-14% Ca
  • Like SSP, TSP supplies both calcium and phosphate

MAGNESIUM

Dolomite

  • 22% Ca and 12% Mg, depending upon the source
  • Dolomite is a source of both Ca and Mg, in addition to its liming affect.

Magnesium sulfate (Epsom salt)

  • 9.8% Mg and12% S
  • Epsom salt is very soluble and does not alter soil pH.

Magnesium oxide

  • 55% Mg
  • Magnesium oxide increases soil pH.
  • It is not highly water soluble. For maximum reactivity, it is often mixed into the soil.

SULFUR

Elemental sulfur

  • In its elemental form, sulfur is a solid
  • Elemental sulfur is insoluble in water.
  • When finely-ground elemental sulfur is incorporated into the soil, microorganisms oxidize and convert it to sulfate.
    • The finer the sulfur, the greater its oxidization potential when incorporated into the soil.

Ammonium sulfate

  • Contains 24% S and 21% N
  • Ammonium sulfate can have a strong acidifying effect on soil

MICRONUTRIENT

Iron

  • Iron (ferrous) sulfate
    • Contains19% Fe
    • May be used as a foliar spray to correct Fe deficiencies
  • Iron chelate (iron EDTA)
    • Contains 5-14% Fe
    • May be used as foliar spray or directly applied to the soil
    • Though expensive, chelates prevent the formation of insoluble Fe compounds

Zinc

  • Zinc sulfate
    • Contains 35% Zn
    • Due to its low soil mobility, zinc sulfate should be mixed into the soil when broadcasted
    • Band placement is favorable in finely textures soils that are low in Zn
    • Available as a foliar spray
  • Zinc chelate (EDTA)
    • Contains 14% Zn
    • May be applied as a foliage spray or directly to the soil
    • Zn chelates are very soluble and may be incorporated into liquid fertilizers

Copper

  • Copper sulfate
    • Contains 25% Cu
    • May be applied to the soil and/or foliage
    • Incorporating Cu into the plant root zone increases the efficiency of Cu
  • Copper chelate (EDTA)
    • Contains 13% Cu
    • Very soluble
    • May be applied as a foliar spray

Manganese

  • Mangenese sulfate
    • Contains 26-28% Mn
    • May be applied as a foliar spray and/or directly to the soil in a band application
  • Manganese chelate (EDTA)
    • Contains 5-12%
    • Not recommended as a broadcast

Boron

  • Sodium borate, or borax
    • Contains 11% B
    • May be applied to soil as a band or broadcast
    • Available as a foliar spray
    • Since boron has a small sufficiency range, it should be mixed uniformly into the soil
    • Care should be taken to prevent B toxicity.
  • Sodium tetraborate
    • Contains14-15%
    • Most widely used B fertilizer

Granusol

  • A manufactured product that contains 5.4% Fe, 5.2% Zn, 5.6% Mn, 5.4% Mg, 2.6% Cu, and 0.5% B. Since it is largely insoluble, it should be incorporated into the soil.

Blends (Mixed Fertilizers)

There are many available inorganic fertilizers that contain various combinations of N, P, and K fertilizers. If a particular formulation of N, P, and K is desired, a blend can conveniently meet the needs of the farmer or gardener, while reducing the costs associated with buying and applying multiple fertilizers.

Fertilizer Calculations

When applying fertilizers to your field or garden, you will add fertilizers at a specific rate of application. To accomplish this goal, it is necessary that you can perform two calculations:

  • First, you must know how to determine the percentage of nutrients, particularly N, P, and K, that a particular fertilizer contains.
  • Secondly, you must know how to calculate the quantity of fertilizer that must be added to a given area in order to achieve the recommended rate of fertilization for a particular nutrient.

The following provides a detailed explanation of how to perform these calculations, which was prepared and written by Jay Deputy of Tropical Plants and Soil Science.

Fertilizer Application Calculations

The major nutrients

A complete fertilizer contains all three of the major nutrient elements nitrogen (N), phosphorus (P), and potassium (K).
The total percentage of the nutrients contained in a fertilizer is given as three numbers, which together is known as the analysis. These numbers are usually in large print on the front of the container or bag. An example would be 10-30-10.

Nitrogen (N)

Nitrogen is reported as total N and may take one of three chemical forms:

  • NO3– or nitrate-N
  • NH4 or ammonium-N
  • Urea-N

Most fertilizers contain a mixture of two or all three of these N forms.

The percent of total-N is represented by the first of the three analysis numbers. For example, a bag with an analysis of 10-30-10 contains 10% N by weight of all nitrogen forms. Therefore, a 50 pound bag of 10-30-10 contains 5 pounds of total-N, which accounts for 10% of the bag’s 50 pounds weight.

Calculation of %N: 10% of 50 pounds = (.10 x 50 pounds) = 5 pounds of total N

Phosphorus (P)

Phosphorus is never present as pure elemental P. Instead, P is reported in fertilizers as the chemical compound P2O5 or ortho-phosphate. The percent of P2O5 in a complete fertilizer is represented by the second of the three analysis numbers. For example, a bag with the analysis of 10-30-10 contains 30% P2O5 by weight. Therefore, a 50 pound bag of 10-30-10 contains 15 pounds of P2O5.

Calculation of % P2O5: 30% x 50 pounds = (.30 x 50 pounds) = 15 pounds of P2O5

However, notice that the above calculation determines the amount of P2O5 in the bag of fertilizer, rather than the amount of total P. To report the quantity of total P, the percent of elemental, or pure, P must be determined.

To calculate elemental P, we must determine the percent by weight of P in P2O5, which is 44%. Thus, 44% of P2O5 is elemental P. To convert the percent of P2O5 to percent elemental P, multiply the percent P2O5 by 44%.

Therefore, a bag of 10-30-10 contains 15 pounds of P2O5 (see above calculation) and 6.6 pounds elemental P (15 pounds P2O5 x .44 = 6.6 pounds P)

Calculation of % P = % P2O5 x 44% = 15 pounds P2O5 (see above calculation) x .44 = 6.6 pounds of P

Potassium (K)

Potassium is also never present as pure elemental K, but is reported as its oxide form of K2O, commonly called potash. The percent of K2O in a bag of blended fertilizer is represented by the third of the three numbers of the analysis. For example, a bag of fertilizer with an analysis of 10-30-10 contains 10% K2O by weight. Therefore, a 50 pound bag of 10-30-10 contains 5 pounds of K2O 10% of 50 pounds.

Calculation of % K2O = 10% of 50 pounds = (.10,x 50) = 5 pounds of K2O

As with P, in some cases potassium is reported as percent elemental (or pure) K. To calculate elemental K, we must determine what percentage (by weight) of K2O is elemental K, which we know to be 83%. This means that 83% of K2O is elemental K. To convert percent K2O to percent elemental K, multiply the percent K2O by 83%.

Therefore, a bag of 10-30-10 contains 5 pounds of K2O (see above calculation) and 4.15 pounds elemental K

Calculation of % K = % K2O x 83% = 5 pounds K2O x .83 = 4.15 pounds elemental K

Calculating fertilizer application rates

The recommended amount of fertilizer to be applied to a crop at any one time has been experimentally determined for the major nutrients. In most cases, the most essential nutrient under consideration is nitrogen. In the case of turfgrass nutrition, the recommended amount of fertilizer per application is given in terms of pounds of nitrogen per acre or per 1000 square feet. The normal recommended rate for turf is one pound N per 1000 sq. ft. The frequency of applications will vary with the species of turfgrass.

In order to calculate the total amount of fertilizer being applied at any one time, several things need to be considered. These are:

  • Recommended rate in terms of pounds of N per 1000 square foot.
  • The analysis of the fertilizer being used. (The quantity of N that the fertilizer contains, which is indicated by the first number of the analysis.) Keep in mind — the lower the N %, the more fertilizer that will be required.
  • The total area being fertilized.
  • Must be mathematically calculated depending upon the overall shape of the plot

Once these have been determined, the following calculation will give the total amount of fertilizer needed to cover the designated area.
(Rate of N / 1000 sq. ft) X (Area in sq. ft) / (% N in fertilizer) = Pounds of fertilizer

Remember that when working with percentage figures, convert to a decimal before calculating. Therefore, convert 33% N to .33 for the calculation

Example 1 
Using a fertilizer with analysis 33-5-5 at a rate of one pound N/1000 ft2, how much fertilizer is required to cover a turf plot that measurers 100 ft x 50 ft.
First calculate the area of the plot,
area = L x W 100 x 50 = 5000 ft2
(Rate of N / 1000 sq. ft) X (Area in sq. ft) / (% N in fertilizer) = Pounds of fertilizer

Example 2 
(1 lb /1000 sq ft) X 5000 sq. ft / .33 = 15.15 lb of 33-5-5 fertilizer
This time use a different fertilizer, 20-5-10 at the same rate on the same plot of turf
(1 lb /1000 sq ft) X 5000 sq. ft / .20 = 25 lb of 20-5-10 to cover the same area

Why the difference?

33-5-5 contains more N per pound of fertilizer, and therefore, requires less material to provide one pound of N / 1000 ft2. However, this is not the only criteria that should be used in deciding what analysis to use. The nitrogen formulation is often a more important consideration.

Organic sources

Proper maintenance of soil organic matter is an important part of nutrient management, as increasingly supported by the scientific community. Organic matter enhances both chemical and biological soil properties, as well as supplying sources as macro- and micronutrients. The most stable form of organic matter—humus—plays an all-important role in improving soil structure, nutrient retention, and water storage. Additionally, it has been shown that additions of animal and green manures, as well as compost, enriched microbial diversity and populations.

NITROGEN

Animal manure

The amount of nitrogen that manure provides and its subsequent availability to plants is influenced by a several factors:

  • Nutrient analysis of the animal feed
  • Storage and handling procedures of the manure
  • Amount and type of materials added to the manure
  • Timing and method of application
  • Properties of the soil
  • Choice of crop

Nitrogen Analysis

  • Manures can contain between 0.5 and 6% total nitrogen, though typical values range from 0.5 to 1.5%.
  • Of the total nitrogen, approximately only 25% to 50% is in the form of ammonium and directly available to plants./li>
  • The remaining 50-75% is organic nitrogen and must be mineralized before it is utilized by plants. Thus, the same conditions for optimal mineralization of organic matter are the same for the optimal mineralization of organic nitrogen in manure.

Organic Nitrogen

Organic nitrogen is further divided into two categories:

  • unstable organic nitrogen
  • stable organic nitrogen

Unstable organic nitrogen

  • urea or uric acid are the primary forms of unstable organic nitrogen
  • mineralization into ammonium occurs rapidly
  • highly vulnerable to volatilization and denitrification losses
  • it is recommended that manure be incorporated into the soil to prevent nitrogen losses to the atmosphere

Stable organic nitrogen

  • mineralizes at much slower rates than the unstable fraction
  • the stable nitrogen that is less resistant to decomposition (approximately 30% to 60% of the total nitrogen) mineralizes during the first year of application
  • the stable nitrogen that is more resistant to decomposition mineralizes during the following years with declining rates of mineralization each year that passes

The following table contains nutrient analysis information for various types of animal manures and composts.

Table 9. Nutrient Composition of Various Types of Animal Manure and Compost (all values are on a fresh weight basis).

Manure Type

Dry Matter

Ammonium-N

Total Na

P2O5

K2O

 

%

————————- lb/ton —————————

Swine, no bedding

18

6

10

9

8

Swine, with bedding

18

5

6

7

7

Beef, no bedding

52

7

21

14

23

Beef, with bedding

50

8

21

18

26

Dairy, no bedding

18

4

9

4

10

Dairy, with bedding

21

5

9

4

10

Sheep, no bedding

28

5

18

11

26

Sheep, with bedding

28

5

14

9

25

Poultry, no litter

45

26

33

48

34

Poultry, with litter

75

36

56

45

34

Turkey, no litter

22

17

27

20

17

Turkey, with litter

29

13

20

16

13

Horse, with bedding

46

4

14

4

14

Poultry compost

45

1

17

39

23

Dairy compost

45

<1

12

12

26

Mixed compost: Dairy/Swine/Poultry

43

<1

11

11

10

aTotal N = Ammonium-N plus organic N 
Sources: Livestock Waste Facilities Handbook, 2nd ed., 1985, Midwest Plan Service; Organic Soil Amendments and Fertilizers, 1992, Univ. of Calif. #21505.

Legume /green manure

A particular advantage of implementing a legume/green manure rotation into the soil/cropping system is the added source of organic matter. However, green manures also improve soil structure by reducing bulk density. Green manures are generally grown for less than a growing season and are plowed under before producing seeds. Examples of common green manure crops are sunnhemp, annual ryegrass, sudangrass, sudex, and sesbania. Legumes, such as sunnhemp and sudex, are particularly beneficial since they are nitrogen fixing species and are a good source of nitrogen.

Management of organic matter also helps to reduce the occurrence of soil erosion, thus improving soil conservation. In addition to rotations of green manures, cover crops, companion plantings, mulching, and stripcropping with grass species can help minimize the depletion of soil resources, as well as providing a good source of organic residue on the soil surface.

Sewage sludge

  • Sewage sludge consists of the solid products formed during sewage treatment
  • It is not uniform in mineral composition
  • Generally, it contains less than 1 to 3% total nitrogen

PHOSPHORUS

Animal manure

  • Animal can contain 0.1 to 0.4% phosphorus.
  • Like nitrogen, the amount of phosphorus in animal manure depends upon several factors, including type of animal feed, handling, and storage of manure.
  • Out of the total amount of phosphorus in fresh manure, approximately 30 to 70% is organic. Thus, mineralization must occur before the organic phosphorus becomes available to plants.

Sewage sludge

  • Sewage sludge contains approximately 2 to 4 % total phosphorus.

Microbial Phosphorus

  • Certain bacteria in the soil are capable of increasing the availability of phosphate, by increasing its solubility.
  • The most abundant P-solubilizer is Bacillus spp.

POTASSIUM

Manures

  • Potassium content may range between 0.2 and 2% in manures.

Sewage sludge

  • Potassium primarily exists as soluble, inorganic K+.

SULFUR

  • Animal manure and Sewage sludge: 0.2-1.5%

CALCIUM

  • Animal and municipal wastes: 2-5% (dry)

MAGNESIUM

  • Animal and municipal wastes: 0.2-1.5%

MICRONUTRIENTS

Animal wastes and municipal wastes

Fe: 0.02% – 0.1% (benefit increased chelation)
Zn: 0.01-0.05%, municipal (up to 0.5%) (benefit chelation)
Cu: Animal small (0.002-0.03%), municipal (0,1%) (natural chelation)
Mn: animal (0.01-0.05%) municipal (0.05%) (chelation)
B: animal (0.001-0.005%) municipal (0.01%) (chelation)
Cl: most low because Cl is highly soluble and mobile
Mo: animal (0.0001-0.0005%) municipal (0.0001%)

Distinctions between manure fertilizers and commercial fertilizers

  • Nutrient analysis: While commercial fertilizers may have a relatively high analysis of the major macronutrients (nitrogen, phosphorus and potassium), the nutrient content of manures is much less.
    • As a result, a larger quantity of manure must be applied to the soil as compared to the addition of commercial fertilizer at an equivalent rate. It may take up to 30 tons of manure per acre to achieve the desired nutrition.
  • The nutrient content of manure fertilizers is highly variable.
    • Factors that affect nutrient content include animal type and diet, handling, storage, and water content.
    • Chicken manure generally contains more nitrogen, but also quickly decomposes and subsequently releases ammonia.
    • Since manure is an organic source, the availability of nutrients is also largely influenced by the biological processes of mineralization and immobilization.

BENEFITS AND DISADVANTAGES OF MANURE FERTILIZERS

Benefits

  • Provides a source of ammonium
  • Increases the availability of certain essential elements, including phosphorus and various micronutrients
  • Increases the mobility of phosphorus and micronutrients in the soil
  • Increases soil organic matter content
  • Improves water holding capacity
  • Increases water infiltration rates
  • Improves soil structure
  • Reduces aluminum toxicity
  • Recycles nutrients

Disadvantages

  • Contains variable nutrient analysis
  • Requires high rates of application due to lower analysis (especially N)
  • Variable quality
  • Undergoes variable rates of mineralization, therefore difficult to predict nutrient availability
  • Less flexibility involved in applying specific nutrient combinations
  • Risk of nitrogen losses volatilization during handling and placement
  • High costs associated with transportation
  • Has relatively low nutrient content per unit weight as compared to mineral fertilizers
  • Potential weed problem through the transfer of weedy seeds which can be minimized through composting

Related Images:

Fertilizer Basics

Fertilizer Nutrients

Plumeria need to be fertilized because most soil does not provide the essential nutrients required for optimum growth. Even if you are lucky enough to start with great garden soil, as your plants grow, they absorb nutrients and leave the soil less fertile. Remember those beautiful blooms and leaves you grew last year? It took nutrients from the soil to build those plant tissues. By fertilizing your plumeria, you replenish lost nutrients and ensure that this year’s plumeria have the food they need to flourish.

There are six primary nutrients that plants require. Plants get the first three—carbon, hydrogen and oxygen—from air and water. The other three are nitrogen, phosphorus and potassium.

Nitrogen helps plumeria make the proteins they need to produce new tissues. In nature, nitrogen is often in short supply so plumeria have evolved to take up as much nitrogen as possible, even if it means not taking up other necessary elements. If too much nitrogen is available, the plumeria may grow abundant foliage but not produce flowers. Growth may actually be stunted because the plumeria isn’t absorbing enough of the other elements it needs.

Phosphorus stimulates root growth, helps the plant set buds and flowers, improves vitality and increases seed size. It does this by helping transfer energy from one part of the plumeria to another. To absorb phosphorus, most plumeria require a soil pH of 6.5 to 6.8. Organic matter and the activity of soil organisms also increase the availability of phosphorus.

There are three additional nutrients that plumeria need, but in much smaller amounts: Potassium improves overall vigor of the plumeria. It helps plumeria make carbohydrates and provides disease resistance. It also helps regulate metabolic activities.

Calcium is used by plumeria in cell membranes, at their growing points and to neutralize toxic materials. In addition, calcium improves soil structure and helps bind organic and inorganic particles together.

Magnesium is the only metallic component of chlorophyll. Without it, plumeria can’t process sunlight.

Sulfur is a component of many proteins.

Finally, there are eight elements that plumeria need in tiny amounts. These are called micronutrients and include boron, copper and iron. Healthy soil that is high in organic matter usually contains adequate amounts of each of these micronutrients.

Organic vs. Synthetic

Do plumeria really care where they get their nutrients? Yes, because organic and synthetic fertilizers provide nutrients in different ways. Organic fertilizers are made from naturally occurring mineral deposits and organic material, such as bone or plant meal or composted manure. Synthetic fertilizers are made by chemically processing raw materials.

In general, the nutrients in organic fertilizers are not water-soluble and are released to the plumeria slowly over a period of months or even years. For this reason, organic fertilizers are best applied in the fall so the nutrients will be available in the spring. These organic fertilizers stimulate beneficial soil microorganisms and improve the structure of the soil. Soil microbes play an important role in converting organic fertilizers into soluble nutrients that can be absorbed by your plumeria. In most cases, organic fertilizers and compost will provide all the secondary and micronutrients your plumeria need.

Synthetic fertilizers are water-soluble and can be taken up by the plumeria almost immediately. In fact applying too much synthetic fertilizer can "burn" foliage and damage your plumeria. Synthetic fertilizers give plumeria a quick boost but do little to improve soil texture, stimulate soil life, or improve your soil’s long-term fertility. Because synthetic fertilizers are highly water-soluble, they can also leach out into streams and ponds. Synthetic fertilizers do have some advantages in early spring. Because they are water-soluble, they are available to plumeria even when the soil is still cold and soil microbes are inactive. For this reason, some organically-based fertilizers, such as PHC All-Purpose Fertilizer, also contain small amounts of synthetic fertilizers to ensure the availability of nutrients.

For the long-term health of your garden, feeding your plumeria by building the soil with organic fertilizers and compost is best. This will give you soil that is rich in organic matter and teeming with microbial life.

Foliar Feeding?

Plumeria can absorb nutrients eight to 20 times more efficiently through their leaf surfaces than through their roots. As a result, spraying foliage with liquid nutrients can produce remarkable yields. For best results, spray plants during their critical growth stages such as transplanting time and blooming time.

What About pH?

Even if proper nutrients are present in the soil, some nutrients cannot be absorbed by plumeria if the soil pH is too high or too low. For most plumeria, soil pH should be between 6.0 and 7.0. A soil test will measure the pH of your soil. You can send a sample to a lab (contact your local extension service for a low-cost kit) or buy a home kit and do it yourself. Lime or wood ash can be used to raise pH; sulfur or aluminum sulfate can lower pH. Keep in mind that it’s best to raise or lower soil pH slowly over the course of a year or two. Dramatic adjustments can result in the opposite extreme, which may be worse than what you started with. Once again, a helpful solution is to apply compost. Compost moderates soil pH and is one of the best ways to maintain the 6.5 ideal.

Slow-release, granular Excalibur 11-11-13 or similar fertilizer gives your plumeria all the nutrients they need, including plenty of phosphorus for big, abundant flowers. For a healthy start, mix a handful into the soil at transplant time and at the beginning of your growing season.

How to Choose a Fertilizer

In most cases, an all-purpose, 11-11-13 fertilizer with micronutrients such as Excalibur will provide the nutrients all plumeria need for healthy growth. If a soil test reveals certain nutrient deficiencies, or if you want to tailor your fertilizer to the needs of particular plumeria, you can select a special formulation. What you choose will depend on your soil and what you are growing.

The three numbers that you see on a fertilizer label, such as 11-11-13, tell you what proportion of each macronutrient the fertilizer contains. The first number is always nitrogen (N), the second is phosphorus (P) and the third is potassium (K). This "N-P-K" ratio reflects the available nutrients —by weight—contained in that fertilizer. For example, if a 100-pound bag of fertilizer has an N-P-K ratio of 11-11-13, it contains 11 pounds of nitrate, 11 pounds of phosphate (which contains phosphorus), 13 pounds of potash (which contains potassium) and 84 pounds of filler.

Note that the N-P-K ratio of organic fertilizers is typically lower than that of a synthetic fertilizer. This is because by law, the ratio can only express nutrients that are immediately available. Most organic fertilizers contain slow-release nutrients that will become available over time. They also contain many trace elements that might not be supplied by synthetic fertilizers.

To build the long-term health and fertility of your soil, we recommend using granular slow release fertilizers with micronutrients. Supplemented with a water-soluble fertilizer ensures that your plants have the nutrients they need when they’re in active growth.

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Potassium (K)

Potassium is a chemical element with symbol K (derived from Neo-Latin kalium) and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction and burning with a lilac flame. Naturally occurring potassium is composed of three isotopes, one of which, 40K, is radioactive. Traces (0.012%) of this isotope are found in all potassium making it the most common radioactive element in the human body and in many biological materials, as well as in common building substances such as concrete.

 

Because potassium and sodium are chemically very similar, their salts were not at first differentiated. The existence of multiple elements in their salts was suspected in 1702, and this was proven in 1807 when potassium and sodium were individually isolated from different salts by electrolysis. Potassium in nature occurs only in ionic salts. As such, it is found dissolved in seawater (which is 0.04% potassium by weight), and is part of many minerals.


Most industrial chemical applications of potassium employ the relatively high solubility in water of potassium compounds, such as potassium soaps. Potassium metal has only a few special applications, being replaced in most chemical reactions with sodium metal.

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Macronutrients

Micronutrients are those elements essential for plant growth which are needed in only very small (micro) quantities . These elements are sometimes called minor elements or trace elements, but use of the term micronutrient is encouraged by the American Society of Agronomy and the Soil Science Society of America. The micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants.

Nitrogen (N)

  • Nitrogen is a part of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy.
  • Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis.
  • Helps plants with rapid growth, increasing seed and fruit production and improving the quality of leaf and forage crops.
  • Nitrogen often comes from fertilizer application and from the air (legumes get their N from the atmosphere, water or rainfall contributes very little nitrogen)

Phosphorus (P)

  • Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis.
  • Involved in the formation of all oils, sugars, starches, etc.
  • Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress.
  • Effects rapid growth.
  • Encourages blooming and root growth.
  • Phosphorus often comes from fertilizer, bone meal, and superphosphate.

Potassium (K)

  • Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium.
  • Helps in the building of protein, photosynthesis, fruit quality and reduction of diseases.
  • Potassium is supplied to plants by soil minerals, organic materials, and fertilizer.

Calcium (Ca)

  • Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant. It is also thought to counteract the effect of alkali salts and organic acids within a plant.
  • Sources of calcium are dolomitic lime, gypsum, and superphosphate.

Magnesium (Mg)

  • Magnesium is part of the chlorophyll in all green plants and essential for photosynthesis. It also helps activate many plant enzymes needed for growth.
  • Soil minerals, organic material, fertilizers, and dolomitic limestone are sources of magnesium for plants.

Sulfur (S)

  • Essential plant food for production of protein.
  • Promotes activity and development of enzymes and vitamins.
  • Helps in chlorophyll formation.
  • Improves root growth and seed production.
  • Helps with vigorous plant growth and resistance to cold.
  • Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels.

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Nutrients

Sixteen chemical elements are known to be important to a plant’s growth and survival. The sixteen chemical elements are divided into two main groups: non-mineral and  mineral.  

Non-Mineral Nutrients

  • The Non-Mineral Nutrients are hydrogen (H), oxygen (O), & carbon (C).
  • These nutrients are found in the air and water. 
  • In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO2 – carbon and oxygen) and water (H2O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant’s food. 
  • Photosynthesis means "making things with light".
  • Since plants get carbon, hydrogen, and oxygen from the air and water, there is little farmers and gardeners can do to control  how much of these nutrients a plant can use.

Mineral Nutrients

The 13 mineral nutrients, which come from the soil, are dissolved in water and absorbed through a plant’s roots. There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many plumeria growers and gardeners use fertilizers to add the nutrients to the soil. The mineral nutrients are divided into two groups:
macronutrients and micronutrients.  

Macronutrients 

Macronutrients can be broken into two more groups: primary and secondary nutrients. 

The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients usually are lacking from the soil first because plants use large amounts for their growth and survival.

The secondary nutrients are calcium (Ca), magnesium (Mg), and sulfur (S). There are usually enough of these nutrients in the soil so fertilization is not always needed. Also, large amounts of Calcium and Magnesium are added when lime is applied to acidic soils. Sulfur is usually found in sufficient amounts from the slow decomposition of soil organic matter, an important reason for not throwing out grass clippings and leaves.

Micronutrients

Micronutrients are those elements essential for plant growth which are needed in only very small (micro) quantities . These elements are sometimes called minor elements or trace elements, but use of the term micronutrient is encouraged by the American Society of Agronomy and the Soil Science Society of America. The micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants.

Soil

In general, most plants grow by absorbing nutrients from the soil. Their ability to do this depends on the nature of the soil. Depending on its location, a soil contains some combination of sand, silt, clay, and organic matter. The makeup of a soil (soil texture) and its acidity (pH) determine the extent to which nutrients are available to plants.

Soil Texture 

(the amount of sand, silt, clay, and organic matter in the soil)

Soil texture affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. This condition is called leaching. When nutrients leach into the soil, they are not available for plants to use.

An ideal soil contains equivalent portions of sand, silt, clay, and organic matter. Soils across North Carolina vary in their texture and nutrient content, which makes some soils more productive than others. Sometimes, the nutrients that plants need occur naturally in the soil. Othertimes, they must be added to the soil as lime or fertilizer.

Soil pH

(a measure of the acidity or alkalinity of the soil) Soil pH is one of the most important soil properties that affects the availability of nutrients.

  • Macronutrients tend to be less available in soils with low pH.
  • Micronutrients tend to be less available in soils with high pH.

Lime – can be added to the soil to make it less sour (acid) and also supplies calcium and magnesium for plants to use. Lime also raises the pH to the desired range of 6.0 to 6.5.

In this pH range, nutrients are more readily available to plants, and microbial populations in the soil increase. Microbes convert nitrogen and sulfur to forms that plants can use. Lime also enhances the physical properties of the soil that promote water and air movement.

It is a good idea to have your soil tested. If you do, you will get a report that explains how much lime and fertilizer your crop needs.

Macronutrients

Nitrogen (N)

  • Nitrogen is a part of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy.
  • Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis. 
  • Helps plants with rapid growth, increasing seed and fruit production and improving the quality of leaf and forage crops. 
  • Nitrogen often comes from fertilizer application and from the air (legumes get their N from the atmosphere, water or rainfall contributes very little nitrogen)

Phosphorus (P)

  • Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis. 
  • Involved in the formation of all oils, sugars, starches, etc.
  • Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress.
  • Effects rapid growth.
  • Encourages blooming and root growth.
  • Phosphorus often comes from fertilizer, bone meal, and superphosphate. 

Potassium (K)

  • Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium. 
  • Helps in the building of protein, photosynthesis, fruit quality and reduction of diseases.
  • Potassium is supplied to plants by soil minerals, organic materials, and fertilizer.

Calcium (Ca)

  • Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant. It is also thought to counteract the effect of alkali salts and organic acids within a plant. 
  • Sources of calcium are dolomitic lime, gypsum, and superphosphate.

Magnesium (Mg)

  • Magnesium is part of the chlorophyll in all green plants and essential for photosynthesis. It also helps activate many plant enzymes needed for growth.
  • Soil minerals, organic material, fertilizers, and dolomitic limestone are sources of magnesium for plants.

Sulfur (S)

  • Essential plant food for production of protein.
  • Promotes activity and development of enzymes and vitamins.
  • Helps in chlorophyll formation.
  • Improves root growth and seed production.
  • Helps with vigorous plant growth and resistance to cold.
  • Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels. 

Micronutrients

Boron (B)

  • Helps in the use of nutrients and regulates other nutrients. 
  • Aids production of sugar and carbohydrates. 
  • Essential for seed and fruit development. 
  • Sources of boron are organic matter and borax

Copper (Cu)

  • Important for reproductive growth.
  • Aids in root metabolism and helps in the utilization of proteins. 

Chloride (Cl)

  • Aids plant metabolism. 
  • Chloride is found in the soil. 

Iron (Fe)

  • Essential for formation of chlorophyll.
  • Sources of iron are the soil, iron sulfate, iron chelate.

Manganese (Mn)

  • Functions with enzyme systems involved in breakdown of carbohydrates, and nitrogen metabolism. 
  • Soil is a source of manganese.

Molybdenum (Mo)

  • Helps in the use of nitrogen
  • Soil is a source of molybdenum. 

Zinc (Zn)

  • Essential for the transformation of carbohydrates.
  • Regulates consumption of sugars.
  • Part of the enzyme systems which regulate plant growth. 
  • Sources of zinc are soil, zinc oxide, zinc sulfate, zinc chelate.

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Nitrogen deficiency guide

Nitrogen deficiency guide

Nitrogen is one of the important elements a plant needs. It is an important part of proteins, chlorophyll, vitamins, hormones and DNA. Because it is a component of enzymes, nitrogen is involved in all enzyme reactions and plays an active role in the plant’s metabolism. Nitrogen is mainly absorbed by the plant in the form of nitrate and ammonium. It can also be absorbed via small organic molecules.

It is important that the balance between nitrate and ammonium is correct in the feeding otherwise the pH in the rhizosphere (environment immediately surrounding the roots) will become too high or too low. Plants with nitrate as their source of nitrogen have a higher organic acid content. This has an influence on the taste and storage life of the harvest among other things.

Nitrate is converted into ammonium in the plant by the nitroreductase enzyme. Ammonium is then assimilated into organic molecules. Nitrogen has a positive influence on the plant’s growth. The plant gets bigger leaves, more branches and the vegetative period is extended.

About nitrogen in short

What is it and what does it do?
Nitrogen is a component of enzymes and is therefore involved in all enzyme reactions and plays an active role in the plant’s metabolism.
What can you see?
Purple stalks.
Yellowing leaves.
Leaves fall of.
What can you do?
Raise EC of the feeding or add extra nitrogen.

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Symptoms of a deficiency

Stalks will turn purple, quickly followed by larger leaves in the middle and top parts of the plant, leaves will turn more yellow and finally the leaves whither and fall off.

Development of a deficiency

  • The plant is a lighter color as a whole.
  • Larger leaves in the lower part of the plant turn light green. The leaf stalks of the smaller leaves now also turn purple. Typical vertical purple stripes appear in the stem.
  • Leaves in the lower part of the plant turn more yellow and then become white.
  • The growth is visibly inhibited giving shorter plants, thinner stems, less leaf formation and smaller leaves.
  • Further yellowing and whitening occurs in the top and middle parts of the plant.
  • Leaves on growing points remain green longer but they are a lot less green than at normal nitrogen levels.
  • Forced flowering starts and there is substantial leaf loss. Substantial reduction in yield.

infocourier-nitro_text_3.jpg

Reasons for a deficiency

Deficiency can be caused by incorrect feeding or giving feeding that contains insufficient nutrient elements. Substrates that contain a lot of fresh organic material can cause nitrogen deficiency because micro-organisms bind the nitrogen. A lot of nitrogen can be bound, particularly in the first weeks; this is released later but it is generally too late.

Solutions to resolve a deficiency

Raise the EC of the feeding and rinse the substrate well with it.

  • Add nitrogen yourself to the feeding solution by using urea, blood meal, semi-liquid manure or by using a special “mono-nutrient’ product.
  • Spray the underside of the leaves with a nitrogen solution. This can best be done at the end of the day, just before the lights are turned off. Be careful not to cause burning.

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Phosphorus deficiency guide

 

phosphorusPhosphorus (K) deficiency guide

Phosphorus plays an important role for all living organisms and is an essential nutrient element for plants and animals. It has a key position in the combustion processes of the cell, and in the total energy transfer of the plant. It is also a “building block” of the cell walls, the DNA, and all sorts of proteins and enzymes.
 

For young plants, the presence of phosphate is indispensable; about 3/4 of the phosphorus consumed during a plant’s life cycle is absorbed in the first quarter of its life. The largest concentrations of phosphorus are found in the developing parts of the plant: the roots, the growth shoots and the vascular tissue.

 

About phosphorus in short

What is it and what does it do?
Phosphorus holds a key position in both cell processes and total energy transfer of the plant.
Also a “building block” of – among others – cell walls and DNA.
What can you see?
Small plant with purple/black necrotic leaf parts.
Leafs become malformed and shriveled.
What can you do?
Mix inorganic phosphate fertilizer THOROUGHLY through the potting mix or add extra liquid phosphate when growing in hydroponics.

Symptoms of a deficiency

Plants remain rather small with purple-black necrotic leaf parts, which later on become malformed and shriveled.

Development of a deficiency

  • At first, the plant becomes dark green – a different sort of dark green (blue/ green) as appears when there is a shortage of phosphorus.
  • The growth in height, and the development of the plant’s side shoots are inhibited.
  • After 2 to 3 weeks, dark purple-black necrotic spots appear on the old and medium-old leaves, making the leaves malformed.
  • The purple/black necroses expand to the leaf’s stem. The leaf turns, curls considerably and dies off.
  • The dead leaves are curled and shriveled, have a typical orange purple color, and fall off.
  • The plant flowers fully, but the yield will be minimal.

Reasons for a deficiency

Due to the low concentrations in which phosphate appears in nature, the affinity of plant cells for phosphorous allows easy absorption through the whole root. Therefore, shortages do not happen very often, except when:

  • The growing medium has a too high pH (higher than pH 7). In such cases the plant can not absorb phosphorus due to the fact that insoluble phosphorous compounds develop.
  • The ground is too acidic, or too rich in iron and zinc. This hinders the absorption of phosphate.
  • The potting mix has become fixated. Phosphate can not be absorbed any more.

Solutions to a deficiency

Always use inorganic phosphates as these are easy to absorb. Also always mix the phosphate fertilizer thoroughly through the potting mix.

  • When pH is too high, acidify the medium by using a thinned solution of phosphoric acid.
  • Choose products that have a guaranteed phosphate percentage on the packaging instead of alternative phosphate-containing products like guano or manure.

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Calcium (Ca) deficiency guide

 

calciumCalcium deficiency guide


Calcium occurs throughout the entire plant. It is used for many processes in the plant, however, calcium is most important for the growth process. It has a regulating effect in the cells and contributes to the stability of the plant. Plants have two transportation systems at their disposal: the xylem vessels and the sieve vessels.
 

Most nutrients can be transported via both systems, however, for calcium this is not possible. Since calcium can be transported almost exclusively via the xylem vessels, it is an element that deposes of little mobility within the plant. It is, therefore, important that a sufficient amount of calcium is always available in the root environment, so that it will be continuously available for absorption by the plant.

 

About calcium in short

What is it and what does it do?
Calcium is important to the growth process.
Has a regulating effect in the cells and contributes to the stability of the plant.
What can you see?
Yellow/brown spots, surrounded by a sharp brown outlined edge.
What can you do?
Add calcium by applying a liquid lime fertilizer such as a calcium nitrate solution.

infocourier-calcium_text_4.jpg

 

Symptoms of a deficiency

The older, larger leaves just above the bottommost ones will show the first symptoms. Yellow/brown spots occur, which are often surrounded by a sharp brown outlined edge. In addition, the growth is curbed and in serious cases the tops are smaller than normal and do not close.

 

Development of a deficiency

The symptoms often appear quickly; within one or two weeks the first spots being visible on the older leaves. The spots usually start as small, light brown specks that increase in size over time.

  • After two weeks, the older leaves show ever increasing spots and the spots also often appear at the edge of the leaves, as with a potassium deficiency or with scorch symptoms. The spots have a sharp outline and do not originate exclusively at the edge of the leaves. A lag in development is often already noticeable within a week.
  • Sometimes the growing points will wrinkle up and around the fruits you will find thin, small leaves that are not spotted.
  • The older leaves die off slowly and yellowish cloudy spots may appear around the necrotic spots. The older the leaf is, the more serious the symptoms are.
  • The flowering is also hindered and slowed down. Fruits stay small.

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Reasons for a deficiency

  • Culture on calcium fixing potting mix.
  • An excessive amount of ammonium, potassium, magnesium and/ or sodium in the root environment. The absorption is curbed mostly by ammonium and least by sodium.
  • Problems with the evaporation caused by an excessively high EC value or by excessively high or low relative humidity.

Solutions to a deficiency

  • If the EC value of the substrate or the potting mix is too high, it can be easily rinsed out with pure and if necessary acidified water.
  • Additional calcium can be applied through the nutrient solution by means of liquid lime fertilizers such as a calcium nitrate solution. With an excessively acidic potting mix, lime milk can be used to increase the pH. Use the appropriate potting mix that is not too acidic. Acid potting mix often contains insufficient amounts of lime. Good potting mix and Coco substrates are already limed.

For your information: Be careful with fertilizers containing chloride.

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Magnesium (Ca) deficiency guide

 

magnesium-elementMagnesium deficiency guide

Magnesium is an indispensable element for – amongst others – plants. In plants, it represents a building block for chlorophyll (leaf green), and therefore, it is essential for photosynthesis. At the same time, magnesium plays an important role in the energy transfer. Together with calcium, it is also a component of tap water, influencing water hardness. Inorganic magnesium fertilizers are produced using the same bases that are used to produce potassium fertilizers.

About magnesium in short

What is it and what does it do?
Magnesium is indispensable to plants as it is essential for photosynthesis.
Represents a building block for chlorophyll.
What can you see?
Rusty brown spots.
Cloudy, vague yellow spots between the veins.
What can you do?
Spray with a 2% solution of Epsom salts every 4-5 days during about a week.

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 Symptoms of a deficiency

When there is a shortage, the leaf green in the medium-old leaves under the flowering top will be broken up, and the magnesium will be transported into the young parts of the plant. This breakdown is visible as rusty brown spots and/ or vague, cloudy, yellow spots between the veins. A slight shortage of magnesium hardly affects flowering, although the development of the flowers make the deficiency symptoms worse.

Development of a deficiency

  • Signs of a deficiency first appear around the 4th-6th week. Small, rusty brown spots and/or cloudy yellow flecks appear in the middle-aged leaves (under the top of the plant).
  • The color of the young leaves and the fruit development are not affected.
  • The size and number of rust-brown spots on the leaves increase.
  • The symptoms spread out over the whole plant, which looks ill. When the shortage becomes acute, the younger leaves are also affected and the flower production will be reduced.

Reasons for a deficiency

The magnesium deficiency can occur because uptake is inhibited because of:

  • A very wet, cold and/or acidic root environment.
  • A high quantity of potassium, ammonia and/or calcium (for instance high concentrations of calcium carbonate in drinking water, or clay potting mixes rich in calcium) in comparison with the quantity of magnesium.
  • A limited root system and heavy plant demands.
  • A high EC in the growing medium, which hinders evaporation.

infocourier-magnes_text_3.jpgSolutions to resolve a deficiency

  • When a shortage is diagnosed, the best thing to do is to spray with a 2% solution of Epsom salts.
  • Fertilization via the roots: Inorganic: Epsom salts on hydroponics or Kieserite (magnesium sulphate mono hydrate). Organic: composted turkey or cow manure.

Recovery

Rectify the possible causes: In potting mixes, when the pH is too low (less than 5), use magnesium containing calcium fertilizers. In hydro, temporarily apply a nutrient solution with a higher pH (6.5). When the EC is too high, rinse and/or temporarily feed with drinking water only.

When growing indoors, keep the root temperature between 20 – 25 degrees Celsius. A little extra magnesium is not particularly harmful. When growing in potting mixes, excessive quantities of magnesium do not appear quickly. Too much magnesium inhibits the uptake of calcium, and the plant displays general symptoms of an excess of salts; stunted growth, and dark-colored vegetation.

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Iron deficiency guide

Iron deficiency guide

Iron is a vital element for plant life. Iron has a number of important functions in the overall metabolism of the plant and is essential for the synthesis of chlorophyll. In general, iron is poorly absorbed by the plant. It can only be sufficiently taken up by the roots in certain forms and under proper conditions.

Potting mixes seldom contain too little iron, but it is possible that forms of iron that can be absorbed by the plant are lacking. The absorbency of iron is strongly dependent on the pH. Usually, there is sufficient iron present in absorbable form in acidic potting mixes.

About iron in short

What is it and what does it do?
Iron has a number of important functions in the plant’s overall metabolism and is essential for the synthesis of chlorophyll.
What can you see?
Strong yellowing of especially the young leaves and growth shoots between the veins.
What can you do?
The best thing is to spray the plants with a watery solution of EDDHA or EDTA chelates.

infocourier-iron_text_4.jpg

Symptoms of a deficiency

Iron deficiency can occur during periods of heavy growth or high plant stress and is characterized by a strong yellowing of the young leaves and the growth shoots between the veins. This occurs chiefly because iron is not mobile in the plant. The young leaves can’t draw any iron from the older leaves. With a serious iron shortage, the older leaves and the smaller veins in the leaf can also turn yellow.

Development of a deficiency

  • Green/yellow chlorosis, from inside to the outside in the younger leaves and in the growth shoots. The veins remain mostly green.
  • Continued yellowing of the leaves to sometimes almost white. Also, large leaves turn yellow. This inhibits growth.
  • In serious cases the leaves show necrosis, and the plant’s growth and flowering are inhibited.

infocourier-iron_text_3.jpg

Reasons for a deficiency

  • The pH in the root environment is too high (pH> 6,5).
  • The root environment contains a lot of zinc and/or manganese.
  • The concentration of iron is too low in the root environment.
  • The root temperature is low.
  • The root medium is too wet, causing the oxygen supply in the roots to stagnate.
  • The root system functions inefficiently due to damaged, infected or dead roots.
  • There is too much light on the nutrition tank; light promotes the growth of algae. Algae also use up the iron and break down iron chelates.

Solutions for a deficiency

  • Lower the pH.
  • Iron chelates can be added to the substrate.
  • Drainage can be improved, or the ground temperature can be increased.
  • A leaf nutrient with iron chelates can possibly be applied. If a good fertilizer is used with hydroponic growing, an iron deficiency is almost out of the question.
  • The best thing you can do is to spray the plants with a watery solution of EDDHA (max. 0.4 grams per gallon) or EDTA chelates (max. 2 grams per gallon).

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