First of all, cannabis growers often add a lot of nutrients to their grow mix. However, doing this can sometimes cause more bad than good. We will take a look at how to feed cannabis plants without overdoing it.
All the chemical elements plants need to live and flourish are naturally found in water, soil, and air. It is normal for growers to want to add extra nutrients. This is usually with increasingly better mixes and formulas to take the most out of every single plant. People often spend lots of money on the most advanced nutrients, yet this is no guarantee of a successful grow. So, what kind of nutrients do cannabis plants really need, and how much?
Cannabis plants need:
These three elements are essential for cannabis to grow and thrive (N, P, K are the symbols for these elements). These elements are not alone in the growing mix and are usually combined with more complex molecules that plants are able to absorb. Organic fertilizers contain N, P, and K under more natural forms than the equivalent mineral ones.
Growing in soil is the simplest way to cultivate cannabis, as it can forgive any feeding mistakes. Thanks to its protective barrier between chemicals and the roots system. Some growers like to pump as many nutrients into their plants as possible. Others prefer to keep fertilizing to a minimum. While keeping optimal nutrition will certainly help your cannabis grow as strong as it can be, getting too involved in feeding can cause a distraction in less experienced growers.
Three Diets for Three Stages
Each stage of a plant’s life requires slightly different nutrients. When growing in good and rich soil, no additional nutrients are needed during the seedling stage. Just make sure pots are large enough to provide enough soil and room for the plant’s roots to grow freely.
When growing in artificial mediums that have no natural nutrients, root boosters and seedling nutrition are recommended. Root boosters contain enzymes, bacteria, and other compounds that encourage healthy root systems. Seedling nutrients contain a mix of the three main nutrients, usually in the correct percentage for germination. A similar nutritional effect would be obtained by feeding young plants with feed used during the vegetative stage. This must be done at a quarter of the normal vegetative nutrient dose.
Remember: unless the fertilizer is specifically produced for cannabis, there is a good chance it will be too strong and will need reducing in dose.
In this stage, plants need high nitrogen and potassium levels and a medium intake of phosphorous. As a rule of thumb, the amount of phosphorous should be around half of nitrogen and potassium levels can be about a third to half of the nitrogen.
During the flowering stage, the nitrogen level must be lowered a lot. Now phosphorous can be increased and maintained at the same level of potassium used in the vegetative stage. All commercial cannabis fertilizers are made for veg and bloom phases according to these basic principles.
So, switching to the proper nutrient mix when plants start flowering just means feeding them with a different NPK balance. Nitrogen, phosphorous, and potassium percentages are indicated on the product labels. An example of this is 8-10-15 with each number indicating the ratio of N, P and K. The correct proportions of these three main elements are calculated by the manufacturer.
In addition to the NPK mix, cannabis actually needs small quantities of secondary and micronutrients. Some of these are more important than others for the plant’s health. Most are already present in a good quality soil mix. Others are often included in cannabis feed in addition to NPK. Special additives can also be bought, but this is only advisable for more experienced growers.
Under and Over Feeding
When growing cannabis, it is always better to be cautious than over-enthusiastic. A plant growing with just a little extra feed will develop better yields than a plant growing in over-fertilized soil. Add nutrients to water only every other watering. If you are in doubt about the nutrients then just cut them in half. These are the simplest guidelines for feeding a cannabis plant.
Nutrient deficiencies and overdoses can be detected by a change in the plant’s appearance and color. Many symptoms of overfeeding have similar traits to those of nutrient deficiency. The easiest signs of a nutrient unbalance are drooping and yellowing leaves, irregular leave shape or brown spots and burnt edges. Yellowing leaves only signal a problem in the vegetative and early flowering stages. Noteworthy, yellow leaves are normal (and a welcome site) when happening towards the end of the flowering stage.
If you find that you are not capable of fixing a problem through a correction in nutrition, flush the soil with pure water at a neutral pH for a few days. After this, start again with the nutrient mix at half dose. Remove the top few centimeters of soil which are likely full of excessive nutrients. This will give you a clean start and you can begin feeding again.
- PH is critical for correct nutrient uptake by your cannabis plants. All fertilizers modify water and grow medium pH to some degree that is usually lower. A wrong ph level locks out nutrients from plants and causes an underfeeding situation even if you are adding the correct nutrient mix to water. Because of this, always keep a close eye on the pH of your grow and adjust it with solutions if needed.
- Nutrients are often stored within the cannabis plant itself after absorbing them. This can result in a bad chemical taste in the final product. Most growers stop fertilizing a few days or even weeks before harvest and flush their soil to force the plants to use up these excess nutrients. This results in smoother and better-tasting smoke.