Cannabis Nutritional Needs Go Beyond N-P-K

By Griffin Greenhouse Supplies|April 21, 2022

Cannabis calcium deficiency on the left; calcium deficiency in the form of tip burn on lettuce on the right. Photos: Griffin

The nutritional needs of cannabis and hemp goes beyond the macronutrients of nitrogen, phosphorus, and potassium. Calcium and magnesium, two secondary plant nutrients, also play important roles in plant development and productivity. Cannabis is a particularly heavy consumer of both.

What exactly are these two nutrients doing inside your plants? Calcium provides structural support to plants as they develop, strengthening cell walls as new tissue grows. Plants lacking in calcium can display symptoms such as tip burn on new growth or pronounced leaf curl. For some crops, calcium deficiency even manifests as damage to developing fruits. While calcium builds the foundations for your plants’ structures, magnesium keeps the energy flowing. Magnesium is the atom at the center of all chlorophyll molecules, enabling plants to photosynthesize. When magnesium is lacking, chlorophyll in older growth breaks down and magnesium is remobilized to new growth, leading to lower leaf yellowing.

It can be difficult to meet the full needs of some crops through the use of complete fertilizers alone. Growers find that fertilizers high in calcium can often affect the pH of their substrate, typically leading to higher pH conditions. Some growers avoid with these conditions by rotating fertilizers, while others carefully build balanced fertilizer programs.

An additional option is selecting specialized calcium supplements without adding a complete fertilizer package. Plant-Prod MJ Spike (CaMg) is part of the cannabis-specific line of nutrients from Master Plant Prod. This product has been specifically formulated to deal with the high calcium demands of cannabis production and can be used any time throughout the production cycle. Both calcium and magnesium are provided in a beneficial ratio of 2:1 – 5.4% Calcium, 2.7% magnesium. Chelation with EDTA keeps the nutrient ions fully soluble while in stock tanks and during application. This highly specialized product is free from any other nutrients, ensuring that other nutritional ratios are not thrown out of balance.