Gardening on a budget? Keen to choose natural methods? Concerned about the environment? Prefer not to purchase fertilizers advertised for growing cannabis? There are many good reasons for making your own fertilizer. This post has been brought to you by the letters N, P, and K!
Cannabis plants, like all members of the plant kingdom, need nutrients to thrive. In fact, it’s important to remember that the soil is what is being fertilized, not the plants themselves. Soil contains a complex miniature ecosystem of microbes that act like the plants’ digestive system, breaking down nutrients into a form that can be absorbed by the roots and give the plant the building blocks it needs to grow healthily. The primary nutrients required by cannabis plants are nitrogen, phosphorus, and potassium.
N, P, K – as easy as A, B, C
These three vital nutrients are known by initials for short. N stands for nitrogen, P stands for phosphorus, and K stands for potassium. Wait, K stands for potassium? Are we high? No, K is short for kalium, the Neo-Latin name for potassium. On commercial fertilizer packaging, the three numbers that appear refer to the ratio of N, P, and K, always in that order. The ratio is important because cannabis plants need different levels of fertilizers depending on what stage of their life cycle they are in.
What fertilizers should be used when in the cannabis plant life cycle?
During vegetation, cannabis plants need high levels of nitrogen, which is used for developing healthy and plentiful leaves and stems, and medium levels of phosphorus, which is necessary for good root systems. This feeding program should be continued for the first couple of weeks of flowering, to allow for the ‘stretching’ period, when plants will need plentiful nitrogen. Once flowering is properly underway, levels of nitrogen should be kept low, and levels of phosphorus should be increased, since phosphorus also enables plentiful budding and fruiting. Potassium is needed at all stages, and especially high levels are needed during flowering – preferably, it should be twice the level of nitrogen. Generally, phosphorus tends to increase the number of buds, and potassium increases their bulk and weight.
Where can these nutrients be found?
For beginner gardeners, obviously the easiest solution is to buy a couple of bottles of cannabis fertilizer, one for vegetation and one for flowering. However, there are various reasons that this might not be possible or desirable. So what are the alternatives for those who want to try making their own fertilizer? They can be surprisingly close at hand, in the form of kitchen waste and even human urine! Below we have compiled a list of common substances and what nutrients they contain. Solid substances work best when cut into small pieces and dug into moist soil either prior to planting seedlings or whilst repotting into larger containers. Liquids can be diluted with water and used as liquid fertilizer.
1. Coffee grounds
Coffee grounds are rich in nitrogen and also contain significant levels of potassium and phosphorus, so they are one of the easiest ways to fertilize your plants during vegetation.
2. Banana skins
Contain plenty of phosphorus and potassium, so useful for the flowering period. They also contain calcium and other minerals that are beneficial to cannabis plants.
3. Bean water and beans
Also known as aqua farba, the liquid that chickpeas, white beans, lentils, black beans, broad beans, and many other tinned pulses come in is a source of potassium, as are the beans themselves.
4. Spinach and other vegetable water
Steaming or boiling spinach (and many other vegetables) will leach out some of the nutrients into the water. Once the water has cooled, it can be used as part of a regular watering schedule to add potassium, calcium and iron.
Human urine, when fresh, is a perfectly fine and non-toxic source of nitrogen, phosphorus, and potassium. Nitrogen is by far the largest useful component, so this is another good liquid fertilizer for during vegetation. Urine should also be diluted considerably before being added to the soil – it should never be directly applied to the plants!
Another great way of providing natural and organic fertilizers to cannabis plants is by making organic compost tea. This is slightly more complicated than digging kitchen waste into the soil, but will provide larger batches of food.
What substrates can these natural fertilizers be used with?
When grown in coco coir, rockwool, or other inert substrates, all of the nutrients must be provided by the gardener. This is a tricky mix to get right, and there are plenty of commercially available fertilizers that ensure plants will get everything they need. If hydroponic watering systems are used, it is also preferable to stick to the specialist fertilizers that are designed for them. Attempting to use homemade fertilizers in hydroponic systems inevitably leads to more problems than it solves, as the tubes will clog and unwanted, unpleasant bacteria will swiftly take over your feed tank. Soil, however, is far more forgiving and lends itself to being fed with organic matter. It’s also vital to keep the soil properly hydrated.
We hope you have enjoyed these basic beginner tips for making organic fertilizer. Do you have your own to share? Let us know in the comments!
- Disclaimer:Laws and regulations regarding cannabis cultivation differ from country to country. Sensi Seeds therefore strongly advises you to check your local laws and regulations. Do not act in conflict with the law.