Identifying and preventing nutrient deficiencies is an important part of growing healthy cannabis. Knowing the right nutrients and how to ensure they are absorbed properly, will help your plants produce big yields and unforgettable highs.
The simplest way to identify whether your plant is suffering from a nutrient deficiency, is to examine the symptoms. Here are a few common deficiency signs to look out for in your cannabis garden.
Signs of a Nutrient Deficiency
In order for cannabis plants to grow into the big buds that we love, they need to be properly nourished. This is why many cannabis cultivators monitor their crops closely to identify and prevent nutrient deficiencies before they become a problem.
There are a number of signs that can indicate that your crop is lacking key nutrients. These include yellowing of older leaves, wilting and crinkling of the lower and upper leaves, and mottled brown spots on the leaves.
If your crops are showing these signs, you need to address the issue immediately. This will ensure that your plants stay healthy and strong.
Using a nutrient meter to measure water and runoff can help you to determine whether your plants are uptaking the right amount of nutrients or not. This allows you to adjust the nutrient dosage to keep your plants growing and producing the best buds possible.
Potassium Deficiency
If the lower leaves of your cannabis plant begin to wilt and have yellowing on the edges and between the veins, this could be a sign that you have a potassium deficiency. This is most common on light sandy soils, so make sure to use a potassium rich fertilizer.
Nitrogen Deficiency
Another nutrient that is extremely important to the health of your cannabis crop is nitrogen. Having too little of this mineral will stunt growth and lead to shorter, underdeveloped plants.
Nitrogen is a mobile nutrient, so it can easily be directed to areas of the plant where it is most needed. When nitrogen is not present, your cannabis plants will display symptoms of a nitrogen deficiency such as pale leaves that turn yellow and wilt.
Phosphorus Deficiency
Similar to nitrogen deficiency, phosphorus deficiencies can show up on your cannabis plants as pale green or yellow leaves with mottled brown spots. This issue is often a result of a pH imbalance, so be sure to regularly check your soil’s pH to ensure that it remains within optimal range.
Manganese Deficiency
Symptoms of a Nutrient Deficiency
A nutrient deficiency is a serious issue that can lead to decreased yields, poor plant health, and even death. This is why it’s important to know how to identify and prevent a nutrient deficiency in your cannabis plants.
A common symptom of a nutrient deficiency is that the leaves of the cannabis plant become pale or lime green. This is a sign that the marijuana plant is lacking a key nutrient such as nitrogen.
Nitrogen is one of the most critical nutrients for your marijuana plant, and it’s essential to photosynthesis as well as sugar production. It also helps your plant regulate internal temperatures and transpiration.
You can easily tell if your cannabis plant is suffering from a nitrogen deficiency by looking at the older, lower leaves of the plant. These will appear pale or lime-colored and the tips and edges of the leaves will begin to curl up, losing vigor and shape.
Another symptom that indicates a nitrogen deficiency is that the plant will produce a large amount of new growth which is not receiving enough nitrogen from the old growth. This can happen quickly if you give your plant too much nitrogen from nutrients or if it has been in the flowering stage for too long.
Phosphorus Deficiency (also called a nutrient burn) is another deficiency that affects lower, older leaves. This typically starts out looking like a nutrient burn, but the edges of the leaf may turn brown and look “burned” but yellowing will be visible between the veins.
Zinc Deficiency is another common symptom that occurs on the younger leaves of the plant. This is a result of the zinc in the leaves becoming too low to stimulate the growth cycle and development of new shoots and leaves.
Many nutrient deficiencies can be prevented by making sure the pH levels of your nutrient water solution are balanced correctly. If your nutrient water is too acidic or too alkaline, your cannabis plants can’t properly absorb the nutrients they need to grow healthy.
The nutrients that your cannabis plant needs are divided into macronutrients and micronutrients. The macronutrients are minerals that the cannabis plant requires in large quantities. These include nitrogen, phosphorus, and potassium. The micronutrients are minerals that the cannabis plant needs in smaller amounts, but are vital to their overall health and growth.
Prevention of a Nutrient Deficiency
A nutrient deficiency in a cannabis plant can be detrimental to yield and quality, so it’s important to identify the signs of a deficiency before it becomes a problem. Once you know what the issue is, it’s easy to prevent it from happening in the future by providing your plants with a balanced diet that contains all the essential nutrients they need.
The first step in preventing a nutrient deficiency is to mind the pH level of the grow medium and make sure it’s in the appropriate range. If the pH level is too high or too low, your plant won’t be able to absorb the nutrients it needs.
Nitrogen – This is the most required macro-nutrient for marijuana plants throughout their life cycle. When nitrogen is lacking, you’ll see chlorosis between the veins of older leaves and the plant will slow down in growth. Leafs can also become yellow, curl and eventually drop off.
Phosphorus – This is another important macro-nutrient that cannabis plants need at all stages of their life cycle. Deficiencies in this nutrient can be seen in the form of brown spots on the veins and stems, as well as weak and curled leaves that curl downwards to develop necrotic areas.
Calcium – This is an essential nutrient for the formation of new cells and the movement of vital nitrogen and sugars within the plant. A lack of this nutrient can lead to the development of curled lower leaves, withered root tips at an advanced stage and lower yields.
Magnesium – This is a crucial nutrient for chlorophyll production and helping enzymes produce carbohydrates, sugars and terpenes. A magnesium deficiency can be easily detected in the form of dark green leafs that may adopt a claw-like form.
Sulfur – This is an essential nutrient that helps with the synthesis and breakdown of fatty acids, as well as aiding plant respiration. Sulfur deficiency can be difficult to spot in the early stages of a marijuana plant, as it can be mistaken for calcium or nitrogen deficiencies.
To avoid deficiencies, you should feed your plants with a complete fertiliser that is adapted to the type of culture, substrate and genetics you are growing in. You can also try a larger grow container to reduce the risk of deficiencies in later stages, or refresh your nutrient reservoir more often.
Treatment of a Nutrient Deficiency
Cannabis plants require a range of key nutrients to thrive in an optimal environment. These include nitrogen, calcium, potassium, phosphorus, sulfur and magnesium.
Deficiencies can have serious effects on the health and growth of your marijuana plant, so it’s important to know how to identify a deficiency in your crop. Once you’ve identified a nutrient deficiency, you can treat it properly.
Nitrogen deficiencies typically appear as yellowing and wilting lower leaves that shrivel up and die. The newest, youngest leaves get all the light so they need lots of nitrogen to make energy from sunlight for photosynthesis.
A nitrogen deficiency usually starts in the flowering stage, but can also be a problem during the vegetative phase. The plant will start to “steal” nitrogen from older leaves so newer ones can grow.
When a nitrogen deficiency occurs during the vegetative stage, you can expect your marijuana plant to produce fewer buds and smaller flowers. You can treat this by giving your plants a nitrogen-rich nutrient product, which is available at most gardening stores.
Potassium is another common cannabis nutrient deficiency during the vegetative or flowering phases. It’s essential to the production and movement of sugars and carbohydrates, as well as transpiration, root growth, and water uptake.
As a result, the older leaves will begin to turn brown and soft, then “fold in” and eventually become crispy. A potent foliar feed with potassium is recommended.
Phosphorus deficiencies are more rare than other nutrient deficiencies, but they can occur if you’re growing outdoors in a cold climate or in acidic soil. If your cannabis plants start to develop brown spotting, then it’s likely they’re lacking phosphorus.
If you’re unsure whether your cannabis plants have a nutrient deficiency, it’s best to do a test of the irrigation water you use. Alternatively, take leaf tissue samples to see which nutrients are being absorbed and what isn’t.
Nutrient deficiencies can be prevented by feeding cannabis plants with a balanced mix of essential nutrients, and ensuring the pH level of your nutrient-water solution is correct. It’s a good idea to monitor the nutrient-water solution a minimum of once a week and to rinse your roots with the solution to ensure the plant is absorbing nutrients correctly.
