Organics & nutrient deficiency
by Luis Bartolo
Nutrient deficiencies are caused by too much or too little of one or several nutrients being available. Nutrients are made available between a pH range of five and seven and a total dissolved solids (TDS) range of 800 to 3000 PPM. To maintain these conditions is the key to the perfect nutrient uptake.
To make a plant grow you need over 20 elements. Carbon, hydrogen and oxygen are absorbed from the air and water. Other elements like macro and secondary and microelements are absorbed through the nutrient solution. The macro- nutrients (nitrogen (N), phosphorus (P) and potassium (K)) are the elements that plants need the most. Calcium (Ca) and magnesium (Mg) are secondary elements and are used in smaller amounts. Iron (Fe), sulphur (S), manganese (Mn), boron (B), molybdenum (Mo), zinc (Zn) and copper (Cu) are microelements (=trace elements). Trace elements are found in most soils, but hydroponics fertilizers must contain these trace elements, as they do not normally exist in sufficient quantities in rock wool or water.
Now that we have explained the basic of primary (macro), secondary and micro (trace) elements, let us take a look at the symptoms.
NITROGEN (N)
Nitrogen (N) is primary to plant growth. Plants convert nitrogen to make proteins essential to new cell growth. Nitrogen is mainly responsible for leaf and stem growth as well as overall size and vigour. Deficiency symptoms: Pale plants, red stems, smaller growth. Rapid yellowing of lower leaves progressing up the plant.
Solution : Add any chemical/organic fertilizer containing N. The treatment will take up to a week.
PHOSPHORUS (P)
Phosphorus (P) is necessary for photosynthesis. Furthermore, it works as a catalyst for transferring energy within the plant. Phosphorus will help build strong roots and is essential for flower and seed production. Deficiency symptoms: Slow or stunted growth, red stems. The lower leaves will turn yellow and die.
Solution: Add chemical/organic fertilizer containing Phosphorus. Already affected leaves will not show recovery, but new ones will appear to be normal.
POTASSIUM (K)
Potassium (K) activates the manufacture and movement of sugars and starches, as well as growth by cell division. Potassium increases chlorophyll in foliage and helps regulate stomata openings so plants make better use of light and air. Potassium encourages a stronger root growth, water uptake and triggers enzymes that fight disease. Deficiency symptoms: Affected plants are usually tallest and appear to be most vigorous. Necrotic spots form on lower leaves, with red stems. The leaves appear pale or yellow.
Solution: Add chemical/organic fertilizer containing K.
CALCIUM (Ca)
Calcium (Ca) is fundamental to cell manufacture and growth. Soil growers use dolomite lime, which contains calcium and magnesium, to keep the soil sweet or buffered. Hydroponic growers use calcium to buffer excess nutrients. Calcium moves slowly within the plant and tends to concentrate in roots and older growth. Deficiency symptoms: A lack of calcium in the soil results in the soil becoming too acid. This leads to Mg or Fe deficiency or very slow stunted growth.
Solution: foliar feed the plants with one teaspoon of dolomite lime or cold compressed seaweed per quart of water until condition improves.
SULPHUR (S)
Sulphur (S) is a component of plant proteins and plays a role in root growth and chlorophyll supply. Deficiency symptoms: Plants suffering from S deficiencies exhibit yellowing of new growth.
Solution: Mix one tablespoon of Epsom salts per gallon of water until condition improves.
MAGNESIUM (Mg)
Magnesium (Mg) is found as a central atom in the chlorophyll molecule and is essential to the absorption of light energy. Magnesium aids in the utilization of nutrients, neutralizes acids and toxic compounds produced by the plant. Deficiency symptoms: Lower leaves turn yellow and in the end may even turn white while veins remain dark green.
Solution: Make a foliar application of liquid fertilizers containing Mg. On acid upland soils, apply dolomite or other slow-acting Mg sources to supply Mg and increase soil pH (prevent Al toxicity).
IRON (Fe)
Iron (Fe) is a key catalyst in chlorophyll production and is used in photosynthesis. Deficiency symptoms: Leaves turn pale and veins remain dark green. pH imbalances make iron insoluble.
Solution: Foliar feed with chemical fertilizer containing Fe or rusty water.
MANGANESE (Mn)
Manganese (Mg) works with plant enzymes to reduce nitrates before producing proteins. Deficiency symptoms: Necrotic and yellow spots form on top leaves.
Solution: Foliar feed with any chemical fertilizer containing Manganese.
BORON (B)
Boron (B) is necessary for cells to divide as well as for protein formation. It also plays an active role in pollination and seed production. Deficiency symptoms: Growing shoots turn grey, look burned and can die.
Solution: Use a teaspoon of Boric acid per gallon of water.
MOLYBDENUM (Mb)
Molybdenum (Mn) helps form proteins and aids the plant’s ability to fix nitrogen from the air. Deficiency symptoms: Middle of the leaves turn yellow.
Solution: Foliar feed with chemical fertilizer containing Mb.
ZINC (Zn)
Zinc (Z) is a catalyst and must be present in minute amounts for plant growth. Deficiency symptoms: tips of the leaves and between the veins turn white.
Solution: Burying galvanized nails in the soil can treat Zn deficiency. Chemical fertilizer containing Zn can also be used.
OVER FERTILIZATION
Causes leaf tips to appear yellow or burnt. To correct, soil should be flushed with three gallons of water per one gallon of soil.