Posted on

what nutrients do cannabis plants need to grow

What nutrients do cannabis plants need to grow

Your marijuana plants need calcium, as it is a crucial aspect of cell integrity and overall growth. Calcium helps with the flow of nitrogen and sugars throughout your plants. It is unusual to experience calcium deficiency when plants are grown outdoors. However, it can happen when you grow them in plant mixes.

Please note that most nutrient deficiencies are due to excessively high or low pH levels in your water. Ideally, soil-grown marijuana plants will have a pH of 6.0-7.0. The range drops to 5.5-6.5 if you use coco coir as a growing medium or if you are growing hydroponically. When the pH is at the wrong level, it reduces the plant’s ability to absorb these nutrients.

Magnesium is one of the most important secondary nutrients. It is rare to experience a magnesium deficiency when you grow weed outdoors. However, it is more common when you grow indoors or if you use a soilless medium. It is a crucial player in chlorophyll production. You must infuse your plant with magnesium immediately if you spot signs of deficiency.

The ideal ratio changes throughout the growth cycle of your marijuana plants. For instance, you need a higher proportion of N and K to P during the vegetative stage. A general rule of thumb is to remain close to a 3-1-3 (N-P-K) ratio for the first few weeks.

Sulfur (Semi-Mobile)

It is fairly unusual for marijuana plants to exhibit a phosphorus deficiency. One of the main reasons involves the pH of the water or growing medium going above 7.0. Your plants need phosphorus for photosynthesis. Phosphorus also helps the release of stored energy in carbohydrates.

The first three nutrients listed above – Nitrogen (N), Phosphorus (P), and Potassium (K) – are the most crucial. If you purchase a bag of nutrients from a store, you should notice an N-P-K ratio listed on it.

Calcium and magnesium are often overlooked when discussing the growth of the cannabis plant. It is common to find them together in a single Cal-Mag supplement, which generally contains iron as well. These nutrients are essential to the process of photosynthesis, which involves creating energy from light. Magnesium is particularly crucial for photosynthesis; it is the central atom in the chlorophyll molecule.

Crucial Cannabis Nutrients and Deficiency Symptoms

If you think that nutrient options are confined to marijuana plants that grow in soil, you are wrong! There are also a variety of hydroponic options, which tend to muddy the waters for the uninitiated. But fear not! We’re here to provide an easy guide to selecting the best nutrients for growing marijuana and producing fantastic yields.

Now, let’s take a look at 11 important nutrients for marijuana plants, along with symptoms of deficiency.

What nutrients do cannabis plants need to grow


Calcium is one of the vital properties to the healthy growth of a cannabis plant and is one of the essential secondary macronutrients of plants. Calcium is needed in all phases of growth and is served in multiple functions. It improves the shifting of nutrients and is crucial in allowing the plant to absorb other nutrients. This is the main reason a calcium deficiency leads to other nutrient deficiencies. Calcium strengthens the cell walls in all areas of the plant and benefits the overall health of the plant. With improving the strength of the plant tissue, this allows for better resistance against diseases, pests, and protects your plant from heat stress. Natural sources of calcium include eggshells, lime, and gypsum.


Phosphorus is vital to the growth of a plant and is found in every living plant cell. It acts as a stimulant to support important biological response required for new cannabis growth, such as photosynthesis, metabolism, and nutrient uptake. The cannabis plant depends on the availability of phosphorus during all phases of development. Phosphorus is also one of the most limiting nutrients available globally. Large deposits of rock phosphate that are mined for commercial agriculture are limited to just a few countries making the demand high and the supply slowly decreasing. The most widely used organic amendments are bone meal, soft rock phosphate, high phos bat guano, fish bone meal, seabird guano, and shrimp and crab meal.


Nitrogen is by far one of the most essential nutrients of the cannabis plant. It is so crucial because it is an integral part of chlorophyl and is key in the process of photosynthesis. Plant tissue is also made up of mostly nitrogen, which is why you will quickly see signs of deficiency when there is an absence of it. For a plant to feed itself and grow, there must be a readily available source of nitrogen within the soil or grow medium. Some of the most popular organic elements that are used for nitrogen supplementation include alfalfa meal, blood and bone meal, cottonseed meal, chicken manure, feather meal, fish meal, bat guano, worm castings, and many other natural resources.

When it comes to growing cannabis, the type of nutrients we use play a major factor in determining the level of sustainability that is reached. There are so many elements on earth, from land or sea, that can be used to grow a cannabis plant from seed to harvest. This can be obtained in many ways but the moist sustainable way, is using amendments that are made up of earthly compounds and introduced through the soil. There are many elements and nutrients that are vital to the growth of a cannabis plant but below you will find the 5 nutrients that are an absolute necessity for growing a sustainable crop and the organic elements that are used to introduce this to the plant.