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.

Related Images:


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.

Related Images:

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.


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.


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.

Related Images:

The Role of Phosphorus (P)

Phphosphorus_deficiency1osphorus is a vital component of adenosine triphosphate (ATP), the ‘energy unit’ of plants. ATP forms during photosynthesis, has P in its structure, and processes from the beginning of seedling growth through to the formation of grain and maturity.

The Role of Nitrogen (N)

Nitrogen (N) is essential for plant growth and is part of every living cell. It plays many roles in plants and is necessary for chlorophyll synthesis. Plants take up most of their N as the ammonium (NH4+) or nitrate (No3-) ion. Some direct absorption of urea can occur through the leaves, and small amounts of N are obtained from materials such as water-soluble amino acids.

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.

Related Images:

Potassium deficiency guide

Potassium deficiency guide

It is necessary for all activities having to do with water transport and the opening and closing of the stomata.

Potassium takes care of the strength and the quality of the plant and controls countless other processes such as the carbohydrate system. 

About potassium in short

What is it and what does it do?
Potassium takes care of the strength and the quality of the plant.
Controls countless other processes such as the carbohydrate system.
What can you see?
Dead edges on the leaves.
What can you do?
In case the EC in the substrate or potting mix is high, you can rinse it with clean water.
Add potassium yourself.


Symptoms of a deficiency

Evaporation is reduced if there is a shortage of potassium. A consequence is that the temperature in the leaves will increase and the cells will burn. This occurs mostly on the edges of the leaves, where normally, evaporation is highest.

Development of a deficiency

  • Tips of the younger leaves show gray edges.
  • Leaves turn yellow from the edge in the direction of the veins and rusty colored dead spots appear in the leaves.
  • The tips of the leaves curl up radically and whole sections of the leaves begin to rot. The leaves keep on curling and ultimately fall off.
  • An extreme shortage produces meagre, unhealthy-looking plants with strongly reduced flowering.



Reasons for a deficiency

  • Too little, or the wrong type of fertilizer.
  • Growing in potassium-fixed potting mixes.
  • An excess of sodium (kitchen salt) in the root environment, as sodium slows down potassium intake.

Solutions for a deficiency

  • In case the EC in the substrate or potting mix is high, you can rinse with water.
  • Add potassium yourself, either in inorganic form: Dissolve 5 – 10 grams of potassium nitrate in 2.5 gallons of water. In acidic potting mixes, you can add potassium bicarbonate or potassium hydroxide (5ml in 2.5 gallons of water).
  • Add potassium in organic form: Add a water solution of wood ash, chicken manure or slurry of manure (be careful not to burn the roots). Extracts of the grape family also contain a lot of potassium.

For your information

  • Potassium is absorbed quickly and easily by the plant. In a hydroponic system results get visible within several days. Potassium supplementation by leaf fertilization is not recommended.
  • Too much potassium will cause salt damage, calcium and magnesium deficiencies and acidification of the root environment!

Related Images:

The Role of Potassium (K)

Potassium is a chemical element with symbol K (derived from Neo-Latin, kalium) and atomic number 19. It was first isolated from potash, the ashes of plants, from which its name derives.

Phosphorus (P) Fallacies

A brief review of the macronutrients included in complete fertilizers: nitrogen (N) is involved in photosynthesis as part of the chlorophyll molecule and promotes vegetative growth; phosphorus (P) supports the transfer of energy throughout the plant for root development and flowering; and potassium (K) is an important part of plant metabolism, strengthening its overall health.

Too Much Nitrogen in Plumeria

Nitrogen is a key player in producing chlorophyll; this pigment absorbs sunlight for basic photosynthesis needs. Gardeners must make sure that nitrogen, one of the three macronutrients in soil, is available for root uptake by choosing the right fertilizer. Saturating a garden with high nitrogen levels, however, does not improve plant growth. In fact, it can actually harm a garden more than leaving it to its natural elemental state. Too much nitrogen in plants is apparent both above and below the topsoil.