N – Nitrogen
Nitrogen is a unique element, as plants are able to take up nitrogen in the form of an anion (a negatively charged molecule) or a cation (a positively charged molecule). Plants are able to take up nitrogen in as NO3 or Nitrates and NH4 Ammonium. Plants require or consume more nitrates than ammonia, thus its not. A well balanced nutrient solution will have less than 10% of available nitrogen in the form of ammonia. Nitrogen has many functions in the plant; it is found in proteins, chlorophyll, protoplasm and plant hormones.Source – All premixed nutrients will have adequate nitrogen levels. If a customer wishes to give his plants extra nitrogen in the vegetative stage then he can use Cal-Mag Plus at a rate of 1-2 teaspoons (5-10ml) per gallon. This will supply the plant with 25 – 50ppm extra nitrogen, this will be more than adequate. Using Cal-Mag will also supply the plant with extra Calcium, Magnesium and Iron. If a customer wishes to use an organic source of nitrogen then they can use Mexican Bat Guano. Note that only 1% of the 10% of nitrogen in Mexican Bat Guano is readily available to the plant, the other 9% will slowly be released over a few weeks as the organic nitrogen is broken down. Bat Guano cannot be used in NFT or aeroponic systems; it will also have a limited affect in ebb and flow and drip systems. Bat Guano is ideal for soil growers.
Deficiency – Growth is slow, sparse and spindly the older leaves turn yellow and will eventually dry out and die. The complete leaf will turn yellow, with no green veins.
Toxicity – The plants will produce excess foliage that will be dark green. The plants will also be softer, disease and insect outbreaks will be severe (this will be due to a weaker softer plant). The root system will also be underdeveloped. High nitrogen levels can also retard flowering and fruiting, decrease in yields as flowers don’t set and lower fruit quality. Nitrogen deficiency and toxicity is rear and will not be a problem if growers use premixed nutrients and follow the directions for these nutrients.
P – Phosphorus
Phosphorus is a very important nutrient for plants. It is required by seedlings, newly rooted clones and flowering and fruiting plants. Phosphorus is essential for the development of healthy roots, stimulation of flowering, ripening of fruits and seed production. Phosphorus is also required for the hydrolysis of starch to sugar and for the synthesis of starch to sugars (also known as energy transfer).
Source – Again, premix nutrients will have adequate phosphorus for general plant growth. Plants will need extra phosphorus when the plants begin flowering and fruiting. This is why growers must change from a vegetative formula to a flowering formula. The flowering formulas will have higher phosphate and potassium levels to help stimulate flowering, fruiting and seed production. This all culminates in higher yields and better tasting produce. Taste is increased because of higher synthesis of starch in to plant sugars. For a customer to really boost their yields of flowering and fruiting crops it is advisable for them to use a blooming enhancer. Bloom Booster, Hydroplex, KoolBloom and Bud XL are all products that will boost phosphorus and potassium levels. Bloom Blaster and Monster Bloom must be applied at a rate of 1 teaspoon (5 grams) per 5 galloons of water. Kool Bloom ¼ teaspoon per gallon or 1¼ teaspoons per 5 gallons of water. PK13/14 must be applied at a rate of 1¼ teaspoons (5ml) per gallon of water. For organic growers, in the soil, Jamaican Bat Guano can be used at a rate of 2-3 (10-15 grams) tablespoons per gallon of water.
Deficiency – Plants are stunted and the leaves turn dark green to purplish color. This is due to a buildup of Anthocyanin pigments. These symptoms occur in the older leaves first. Plant maturity will also be delayed and yields will be low. Seed production is also severely affected.
Toxicity – Phosphorus toxicity is very difficult to diagnose. Excess phosphorus will cause deficiencies of calcium, iron, copper and zinc. This will cause confusing signals as other minerals may be showing signs of deficiencies even when adequate amounts of these minerals are present.
K – Potassium
Potassium is the catalyst in plants. It is important for the manufacture and transport of plant sugars/carbohydrates, increases the chlorophyll in leaves, regulates the opening and closing of the leaf stomata and aids in disease resistance, water uptake and ripening process of fruits. Potassium is also found in the juice of fruits which contributes to an increase of fruit taste and fruit quality.
Sources – The sources of potassium are the same for Phosphorus above.
Deficiency – Symptoms occur in older leaves first with yellow blotches and in severe cases dead spots will occur. Branches and stems will weaken and eventually becomes brittle. Flowering and fruiting is diminished and yields are low and poor in quality.
Toxicity – leaf margins may burn in sever cases, but often it will effect the uptake of magnesium and magnesium deficiencies will occur.
Ca – Calcium
Calcium is as important as N, P and K. Calcium is required in the roots, stems, leaves and fruits of plants. It is found in every cell wall and is required for the absorption of nitrogen.
Sources – Most nutrient solutions will have adequate calcium for general plant growth. If a customer is using RO water then they should consider using Cal-Mag Plus. An application rate of 1-2 (5-10ml) teaspoons per gallon of water is sufficient to rectify any deficiencies.
Deficiency – Flower bud development is retarded, thus reducing yields, fruit size is decreased. Roots die, leaving the plant open to root rot attack. Young leaves show symptoms before older leaves. The leaves can be deformed, and have yellow blotches which later turns into dead spots.
Toxicity – No visual symptoms; may cause magnesium deficiency.
Mg – Magnesium
Magnesium is found in the chlorophyll molecule. If a deficiency of magnesium occurs then magnesium is transported from the lower leaves to the new leaves. Magnesium uptake is affected by the concentration of Potassium. If high levels of potassium are applied then the amount of magnesium should increase e.g. at the second week of flowering when blooming enhancers are used then Cal-Mag Plus should be applied.
Sources – Most nutrient solutions will have adequate amounts of magnesium. If a grower is using RO water then Cal-Mag Plus should be used.
Deficiency – Older leaves, lower half of the plants’ leaves show signs of yellowing. The yellowing occurs between the leaf veins which remains green.
Toxicity – There are visual symptoms for magnesium toxicity.
Si – Silicon
Accumulates mostly in the epidermal cells of a plant. It is also found in other cell walls. Silicon helps creates hardier, heavier and stronger plants. It has also been known to increase the plants resistance to fungal attacks.
Sources – Silica Blast and Pro-Tekt (both potassium silicate) and Pyrosol are the main sources of silicon. Growers should take care when using these products as they will increase the pH of the nutrient solution, thus the grower will need to add pH Down to bring the pH back to 6.
Deficiency – Deficiencies of silicon have been known to reduce yields.
Toxicity – Not known.