Nutrition is an indispensable factor in the growth of cannabis. So we need to know what nutrients marijuana needs to properly help marijuana grow healthily.
The nutrients required by cannabis can be divided into three categories: primary, secondary, and micronutrients.
（1）Primary nutrients refer to the major nutrients needed by the plants in large quantities: nitrogen, phosphorus, and potassium. (N, P, K)
Nitrogen(N) is needed for leaf growth and is responsible for making plants greener. The initial characteristic of nitrogen deficiency is yellowing of the lower leaves, while new leaves are green. If left unchecked, eventually all the leaves will turn yellow.
Phosphorus(P) works to develop more bud sites and increase root growth. Cannabis plants that are deficient in phosphorus often exhibit stunted growth and may display symptoms such as purple leaves. This happens, because when phosphorus is deficient, sugars accumulate and cause anthocyanin pigments to develop, sometimes producing a reddish-purple color.
Potassium(K) increases bud production. Potassium deficiency in cannabis is manifested by the yellowing of the leaves from the tips toward the center, ending at the base of the leaves.
（2）Secondary nutrients refer to smaller amounts required than major nutrients: calcium, magnesium, and sulfur. (Ca, Mg, S)
Calcium(Ca) helps transport other nutrients and aids in their absorption.
Magnesium(Mg) is an important component of chlorophyll and plays a key role in photosynthesis and carbohydrate metabolism.
Sulfur(S) in plants helps form important enzymes and assists in the formation of plant proteins.
In general, unless you see signs of a lack of secondary nutrients in your cannabis plant, no additional additions are needed.
（3）Micronutrients are required nutrients, but in very small quantities: boron, chlorine, copper, iron, manganese, molybdenum, nickel, and zinc. (B, Cl, Cu, Fe, Mn, Mo, Ni, Zn)
Micronutrients are needed in much smaller quantities than either essential macronutrients or secondary macronutrients. They are essential to plant life and successful crops. Micronutrients can generally be obtained from the soil, and deficiencies rarely occur. The best long-term way to keep your soil rich with the micronutrients it needs is by adding organic compost. The living things that go into compost — grass clippings, leaves, plants trimmings, table scraps — already contain various amounts of micronutrients. Their presence in your compost guarantees that you’re returning those micronutrients to the soil.
Many research studies have confirmed the benefits of adding silica to the feeding regime of your cannabis crop. Silica reduces the threat of pests and disease, creates plants with stronger cell structures, improves nutrient absorption, protects against metal toxicities, and ultimately improves overall crop performance
Dr. Bruce Bugbee said "The little trichomes in cannabis are full of silica on the leaves and more than in other crops. Cannabis benefits from silica. If you use vermiculite, you automatically get lots of silicon. "
Keep this in mind if you want to add silica as a supplement to your cannabis plant, silica is naturally alkaline and will therefore increase the pH level of the nutrient solution. Silica requires a pH greater than 7 to remain soluble. It is due to this that it cannot be mixed with other nutrients and must be added separately, once all the other nutrients have already been dissolved.
The ration of nutrients
Cannabis needs different amounts of essential macros depending on the stage of development. Cannabis requires more nitrogen during the vegetative and bud formation stages. More phosphorus and potassium are needed during flowering.
Cannabis doesn't need much nutrition at the seedling stage. If not growing in soil, use a rooting booster or seedling nutrient
During the growing stage, and NPK mix that is high in nitrogen (N), moderate in phosphorus (P), and high in potassium (K) works best. it’s good to keep phosphorus at around half that of nitrogen, and potassium at around half to two-thirds of the nitrogen. Begin feeding your plants nutrients once it has its first set of serrated leaves.
During flowering, an NPK mix that is low in nitrogen (N), medium to high in phosphorus (P), and high in potassium (K) works best. This is because a mixture with a high nitrogen content can stunt the development of shoots. Switch to a flowing or nutrient formula when buds start forming on the plant.
pH impact on nutrient availability
Soil pH directly affects the absorption of nutrients and the growth and development of flowers and plants, as well as the availability of various nutrients in the soil. Extreme pH values decrease the availability of most nutrients. Low pH reduces the availability of the macro-and secondary nutrients, while high pH reduces the availability of most micronutrients. Microbial activity may also be reduced or changed.
The range goes from 0 to 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base. The ideal pH range to try to maintain for cannabis is generally accepted to be in the 6.0 to 6.5 range, with some variation depending on the media selected. To determine pH, make sure to perform a soil analysis.
- Cannabis needs different macronutrient ratios for each stage of growth
- Underfeeding or overfeeding your plants can have serious effects on plant health and yields, but it is always better to underfeed than overfeeding. Start with 1/3-1/2 of the recommended dose and increase only when necessary.
- Pay attention to symptoms of nutrient imbalance. Address immediately to avoid a significant loss in yields.
- Test soil pH regularly.
- Flush your plant before harvest. Nutrients are stored in plant which can cause unpleasant chemical taste if the buds are not flushed of the nutrients properly.