Sick Cannabis plants are most often the result of a deficiency in one or more major or minor elements needed for healthy cannabis growth. Therefore being able to diagnose cannabis nutrient deficiencies is the key to correcting the issue and maintaining healthy plants. There is a famous Cannabis Nutrient Deficiency Chart that was published by Jorge Cervantes & Illustrated by Chris Valdes but it is not printer friendly in any way. Also because it is one large illustrated chart it is difficult to use without panning and zooming.
In an effort to correct that, below you will find two tables that are much more computer and printer friendly. The major elements of Nitrogen, Phosphorus & Potassium, combined with the minor elements of Calcium, Magnesium &Sulfur are in the first table. Deficiencies and excess in these elements will cause over 95% of all issues with cannabis plants. The second table contains information about cannabis nutrient deficiencies for trace elements. Issues involving trace elements should be rare.
Printable Cannabis Nutrient Deficiency Chart – Cannabis Nutrient Deficiency Chart PDF
Cultivating cannabis can be a double-edged sword. On one hand, it can be one of the most rewarding things that you will ever do. On the other hand, many of the common cannabis plant deficiencies can make growing marijuana one of the most frustrating things you will ever do.
Is It Really A Nutrient Deficiency?
When a cannabis plant is fed, the plant’s roots absorb nutrients from the moisture and grow medium, or in cases of hydroponics, the water that the roots are suspended in. In layman’s terms, the roots eat the nutrients and get them to where they need to go throughout the plant via a process known as nutrient uptake.
Early Intervention & Frequent Monitoring
Epsom salt is particularly useful because it also includes sulfur and helps cultivators fight off sulfur deficiencies. Sulfur deficiencies can occur during the vegetative phase and the flowering phase, and can be hard to differentiate from a magnesium or nitrogen deficiency.
The ideal range is between pH 5.5 and 6.5 for cannabis, hemp and most fruiting and flowering plants. If the pH is out of your ideal range, we recommend flushing the growing media with clean water or a flushing agent to get a clean start.
Nitrogen toxicity – Contrast to nitrogen deficiency, nitrogen toxicity happens when the plant absorbs too much nitrogen. Signs include dark green leaves, weak stems, and overall slow growth. Leaves can appear to form what is known as “The Claw,” which happens when all the leaves curl inward, making a talon-like shape, which will eventually turn yellow and die. Heat and pH fluctuation will make the claw spread. The majority of nitrogen problems happen when you give your plant too much of it. It’s pretty difficult to give your plants too much nitrogen, therefore paying attention to the amount that your nutrient-solutions contain is important. Nitrogen is really important in the vegetative stage, and less so in the flowering stage. Using a high nitrogen nutrient solution in the vegetative stage and then switching to a lower nitrogen level nutrient solution in the flowering stage will help regulate and maintain the proper nitrogen levels.
Nutrient deficiencies can be avoided by being attentive and careful with the pH level of your nutrient-water solution. The reason your plant is deficient of these nutrients is because they are not getting absorbed. Incorrect levels will lock out certain nutrients thus giving you adverse effects. If you are consistent in feeding your plants their nutrients, it’s probably that the pH is either too high or low and the plant is not absorbing them.
Solutions for Treating Deficiencies in Cannabis
Cannabis requires three primary, or macro-nutrients, for optimal health. These are Nitrogen (N), Phosphorous (P), and Potassium (K), or N-P-K. All plant-food labels include the percentage of these three elements in numerical form, and are presented as N-P-K levels.
Photo courtesy of Royal Queen Seeds
Photo Courtesy of Royal Queen Seeds
“Keeping your cannabis plant healthy requires specific attention to its environment and what you are feeding it.”
It’s important to always start by verifying pH of your growing media when treating deficiencies in cannabis.
Micronutrients are equally important, but only very tiny amounts are required and many, if not all, are readily available in potting soils without the need to add extra. If you are growing hydroponically, then these trace elements are found in most N-P-K solutions–isn’t that handy! These micronutrients, or trace-elements are: Calcium (Ca), Magnesium (Mg), Sulfur (S), Manganese (Mn), Boron (B), Zinc (Zn), Iron (Fe), Molybdenum (Mo), Chlorine (CL) and Copper (Cu).