How to control NPK levels in a cannabis grow
If you are not yet familiar with the term NPK, at BobGrow we want to facilitate the cultivation experience with some simple guidelines for a correct fertilizer and use of external fertilizers with the due contribution of macronutrients.
In growing marijuana, as in most agricultural crops, It is vitally important that plants do not suffer from deficiencies or even excess nutrients for a correct development of the life cycle. Regardless of the chosen substrate, cannabis crops will need a specific supply of nutrients, depending on the moment of the cycle in which they are and the growing medium. So the usual thing is that If the substrate or the type of crop does not contribute enough, it is supplemented externally with the use of different types of fertilizers that will adjust these nutrients, such as NPK levels.
What are the necessary proportions of NPK for marijuana?
As we say, Fertilizers are essential to optimize a cannabis crop. The best known macronutrients to ensure a correct cycle with a good end result are nitrogen (N), phosphorus (F) and potassium (P). Likewise, these three basic nutrients make up the well-known NPK, Of course, it is available in the market according to the proportion that marijuana plants need at the specific moment of cultivation. Obviously the quantities that the plants will need will also depend on the type of marijuana variety chosen.
With all this on the table, it is understood that it is not easy to calculate the NPK levels necessary for growing cannabis, especially without previous experience. But believe us, it seems much more confusing than it really is.
Therefore, below We leave you a simple guide with common recommendations and tips to optimize the subscriber and with it, the final results of cannabis cultivation.
Marijuana needs, deficiencies and excesses according to the cultivation phase
During the first stage of cultivation, marijuana plants will not need a large dose of external fertilizers. That is why we must take care of a possible abuse of initial fertilizer, since an excess of NPK could saturate the crop, not allowing a correct development of marijuana plants. It is as important to provide what is necessary as not to overdo it, especially in this initial phase of the plants.
Likewise, It is advisable during growth to provide a greater supply of nitrogen to the marijuana plants, so fertilizers with a NPK ratio of 3: 1: 1 maximum are used. Of course, depending on the type of cannabis variety chosen, the plants will need variations in nutrient levels, so we always recommend following the advice of both the manufacturer and the specific seed bank.
The nutritional needs of marijuana crops will also vary depending on the substrate chosen. If we choose an indoor crop in soil, as a general rule we will not need to provide the plants with that extra dose of nitrogen, since most substrates on the market are of excellent quality and already contain the necessary proportions even for the growth phase. Likewise, if the area chosen in an outdoor crop already has good levels of nitrogen naturally.
When entering the flowering phase, marijuana plants will require levels other than the NPK macronutrients.
It is relatively simple, since most brands on the market offer differentiated combinations adjusted to each phase. During flowering, we will need differentiated NPK ratios. In the first stage, Until about halfway through the flowering phase, marijuana plants will require a 1: 3: 2 NPK ratio; while from the middle to the end of flowering it is advisable to provide the crop with a ratio of 0: 3: 3, eliminating the contribution of nitrogen and maximizing phosphorus and potassium for the optimization of the final harvest, both in size and in total quantity.
Similarly, it is recommended that during the final week of cultivation a root wash is carried out to eliminate possible rest of fertilization, harmful for final consumption. This root wash can be done with water as is or by using a complementary commercial solution that helps to completely clean the roots of the plants.
As we already said in the flowering phase, each cannabis strain will have its own specific needs, so the ideal as always is to follow the direct recommendations of both the manufacturer and the seed bank to achieve a correct final development of the cannabis cultivation, which will be noticeable in the final result.
Another thing to keep in mind when making external contributions through fertilizers, whether organic or chemical, is not to do it suddenly. We cannot subject the cultivation of cannabis to a sudden change in the fertilizer, since the plants will be affected and possibly lose their absorption capacity by becoming saturated. Therefore, a gradual supply of fertilizers to the subscriber is always recommended so that it is as optimal as possible.