What Are Cannabis Deficiencies?
It’s possible that people might sometimes become deficient in cannabinoids, but the term “cannabis deficiency” doesn’t refer to not having enough Cannabis sativa in your system. It’s used to describe nutrient deficiencies cannabis plants can develop as they grow.
Nutrient deficiencies can reduce the volume or quality of a cannabis plant’s yield or even cause the plant to die. It also takes a trained eye to tell the difference between nutrient deficiencies and excessive concentrations of nutrients, sometimes making matters worse.
What are cannabis deficiencies, and how do they affect the quality of finished cannabis products? Find the answers to these and more questions within this guide.
Can cannabis become deficient in nutrients?
Yes, cannabis plants can become deficient in the nutrients they need to grow properly. Just like humans, plants like cannabis use nutrients to grow and develop according to the plan encoded in their DNA.
Cannabis plants need an exact yet constantly changing ratio of nutrients to grow ideally, and failure to provide cannabis with its needed nutrients leads to disappointing yields. Growing cannabis indoors involves continuous monitoring of nutrient levels and micro-administration of certain nutrients to maintain ideal ratios.
Which nutrients do you use for cannabis?
The primary nutrients that cannabis needs to grow are nitrogen, phosphorus, and potassium. Known as macronutrients and often shortened to just N, P, and K, growers must give these three nutrients to cannabis plants in exact ratios that change throughout the maturation cycle.
This shifting mixture of nutrients is often known as the “NPK ratio.”
Which micronutrients does cannabis need?
In addition to the big NPK trio, cannabis also needs a handful of micronutrients to reach its full potential. Examples of essential cannabis micronutrients include:
- Manganese (Mn)
- Molybdenum (Mo)
- Copper (Cu)
- Iron (Fe)
- Zinc (Zn)
- Boron (B)
Premixed cannabis nutrients rarely contain the exact range and ratio of micronutrients your plants need. As a result, expert growers often mix their own micronutrient brews.
What does nutrient deficiency look like in cannabis?
Different types of cannabis nutrient deficiency have different symptoms. As a grower, it’s worth familiarizing yourself with all the common types of cannabis nutrient deficiency to be able to quickly identify common problems before they intensify. We’ll list a few common deficiencies and their most prominent symptoms below:
- Nitrogen deficiency: Leaves yellow from the tips to the base before falling off
- Phosphorus deficiency: Leaves turn dark green and develop dead, purple splotches
- Potassium deficiency: Leaves yellow and brown but only at edges and tips
- Manganese deficiency: Leaves yellow at the tip and develop small brown spots
- Zinc deficiency: Yellowing of new growth with tips shriveling up
What causes nutrient deficiency in cannabis?
A cannabis plant becomes deficient in nutrients when its roots cannot absorb high-enough nutrient concentrations to supply its aerial parts. Cannabis nutrient deficiency can be caused by failure to provide a plant with proper nutrients, but it can also be caused by root conditions that impair nutrient absorption.
Providing a plant with more nutrients could exacerbate existing issues if root absorption issues aren’t solved first. Giving a deficient cannabis plant too many nutrients can result in nutrient burn, which is just as bad (or worse) than deficiency. As a result, it is absolutely essential to determine the exact causes of nutrient deficiency in cannabis before proceeding.
Can cannabis recover from nutrient deficiency?
A cannabis plant can recover from nutrient deficiency if the cause of the deficiency is properly identified and treated. Parts of the plant that have been affected by deficiency, however, will not regenerate. As a result, only new growth will display the results of the corrected deficiency, making it important to catch deficiencies early in a cannabis plant’s development cycle.
Does cannabis nutrient deficiency affect potency?
Yes, nutrient deficiency can have a profound impact on the potency of harvested cannabis flower. A strain of cannabis that commonly bears 15% CBD, for instance, might yield buds that only contain 10% CBD if it does not receive enough of a particular nutrient during maturation.
Nutrient deficiencies have the most profound impact on cannabis potency during the flowering phase. Even early in a cannabis plant’s life, however, damage due to deficiency can reduce its ability to bear potent buds later on in the maturation process.
Does cannabis flower show nutrient deficiency?
Yes, it’s sometimes possible to identify signs of nutrient deficiency in cannabis buds. Nugs from plants that experienced nutrient deficiency during cultivation often feature fewer crystalline trichomes and orange pistil hairs, for instance. In severe cases of deficiency, entire parts of cannabis nugs can consist of dead tissue, making it necessary to discard the whole bud.
Cannabis nutrient deficiency prevention tips
If you want to make sure your cannabis plants never suffer from deficiencies, here are a few key tips you should follow:
- Check for signs of deficiency early and often. The sooner you notice a deficiency, the less damage it will do.
- Keep the pH of your substrate between 6.0 and 6.5.
- Focus on improving the health of a cannabis plant’s roots since its leaves and buds are simply extensions of its root matter.
- Learn to recognize the differences between nutrient deficiencies and pest activity.
- Consider making your own nutrient blends to achieve an ideal ratio of micronutrients and macronutrients.
- If nutrient deficiency continues to be a problem, rely on the professionals for your cannabis flower needs instead.
Summary: The impact of cannabis nutrient deficiencies
Despite its common nickname, cannabis isn’t just a weed. Sure, it will grow in just about any patch of ground if you scatter a few seeds, but the quality of the flowers that form on a mature cannabis plant directly reflects how they were grown.
Managing nutrients to produce optimal cannabis yields is trickier than it seems. While most professionals have the necessary expertise to avoid burning or starving their plants, amateur growers often accidentally stunt their cannabis plants due to nutrient mismanagement.
That’s why it’s best to go with indoor-grown, artisan-quality cannabis flower. Growing cannabis indoors allows optimal nutrient dosing, and new automation technologies make cultivating weed more accurate and reliable. Learn to spot the most common symptoms of nutrient deficiency in cannabis flower, and only buy buds from companies that give their plants exactly the amount of food they need.
Cannabis deficiency FAQ
Nutrient deficiencies in cannabis are complicated, and there’s always more to learn on the subject. Check out the FAQ section below to enhance your knowledge:
1. How do you tell the difference between nutrient burn and deficiency?
Nutrient burn and nutrient deficiency can often look quite similar, so you’ll need to test the condition of your plant’s roots to tell the difference. The best way to tell the difference between nutrient burn and deficiency is to check the pH level of the runoff water that comes out of your plant’s substrate. If the pH is within acceptable levels, it’s likely that the damage to your plant has been caused by nutrient overuse, not deficiency.
2. Should I remove fan leaves during flowering?
One way growers seek to prevent deficiencies in cannabis plants is by reducing the amount of plant material nutrients have to flow into. Removing up to 30% of your cannabis plant’s fan leaves throughout the flowering phase may improve yields while helping prevent deficiencies. Just remember to remove the leaves gradually using sharp scissors to prevent infections.
3. What does phosphorus deficiency during flowering look like?
During the flowering phase, phosphorus deficiency still most commonly shows itself in the form of yellowing leaves that develop dead, purple splotches and curl up. Flowering plants can also develop signs of phosphorous deficiency directly on their flowers, though. Thankfully, the flowers are usually the last part of the plant to be affected by deficiencies.
4. What are the symptoms of manganese deficiency in cannabis?
If your cannabis plant becomes deficient in manganese, new growth will be lighter in color, especially along the central vein of each leaf. Some leaves may also develop small brown splotches along their central veins.
5. Does cannabis need iron?
Yes, cannabis plants need small concentrations of iron to remain in top form. As a result, this abundant mineral is usually included in cannabis micronutrient preparations. When a cannabis plant is deficient in iron, its new leaves come out entirely yellow.
6. Can epsom salt replace cal-mag?
No, epsom salt is not a good replacement for cal-mag, a type of plant micronutrient combination that includes calcium and magnesium. While epsom salt contains plenty of magnesium, it doesn’t contain any calcium.
7. What is a good source of nitrogen for cannabis?
In nature, cannabis plants receive nitrogen from decomposing substances that pass through soil. As a result, it’s best to replicate this natural nitrogen intake with similarly natural forms of this nutrient.
Manure and guano are excellent sources of nitrogen for plants, for instance, as are earthworm castings. Alfalfa meal, feather meal, and blood and bone meal are additional examples of organic substances you can use to make nitrogen for your cannabis plants.