Diagnosing Nutrient Deficiencies in Cannabis Plants

Symptoms of Nitrogen deficiency include; red stems, small growth, pale appearance to the plant, and a rapid yellowing of the lower leaves that spreads up the plant. To remedy this particular situation, simply add a organic fertilizer containing nitrogen and monitor.

Phosphorous deficiency symptoms include; red stems and slow, stunted, or deformed growth but also include darker green lower leaves as well as leaves that may yellow then die. Adding a organic fertilizer containing Phosphorous can fix this problem but, while improvement to damaged areas may not show, newer growth will appear normal.

Another issue similar to Nitrogen and Phosphorous deficiencies, Potassium deficiency has similar symptoms and include, curling of leaf ends as they die and stretching of the plant. This can be cured by adding a organic fertilizer containing Potassium. Another fix would be to flush the plant with water and half the normal amount of a balanced NPK (Nitrogen, Phosphorous, Potassium) nutrient solution.

Plants lacking Calcium balance can result in the soil becoming too acidic. Calcium deficiency can be fixed by foliar feeding (adding liquid fertilizer directly to plant leaves) one teaspoon of dolomatic lime per quart of water until the plant’s condition approves.

If the new growth of a plant contains yellowing, it is probably suffering from Sulfur deficiency. This deficiency can be cured by mixing one tablespoon of Epsom salts per gallon of water until the plant’s condition improves.

Magnesium deficiency usually starts in the middle of the plant and spreads to the younger leaves. Leaves turning yellow, or even white, with the veins remaining dark green is the best indicator of Magnesium deficiency and can best be cured by spraying with a 2 percent Epsom salt solution.

Pale leaves with dark green veins are indicative of Iron deficiency and can be fixed by foliar feeding with a organic fertilizer containing Iron.

When large amounts of Magnesium are present in the soil, yellow or necrotic (dying or dead) spots will occur on the upper leaves. To cure, foliar feed with chemical fertilizer containing Manganese.

Dead or greying shoots that appear burnt are indicative of Boron deficiency and can be treated with one teaspoon of Boric acid per gallon of water.

Mo deficiency includes yellowing of middle leaves and can be treated by adding organic fertilizer containing Molybdenum.

When white areas form at leaf tips or in between veins, the plant is Zinc deficient. This can be treated by adding organic fertilizer containing Zinc or by burying galvanized nails in the soil.

Indicated by yellow or burnt leaf tips, Over Fertilization can be fixed by flushing 3 gallons of water per every gallon of soil.