A plentiful harvest overflowing with healthy buds is the goal of most cannabis cultivators. Light, oxygen, and water are three of the keys to reaching that goal, but fertilizer is just as essential to increasing bud growth. In this guide to choosing the best marijuana fertilizer, you'll learn why fertilizer is important for marijuana plants along with how and when to use fertilizer to boost flower production and increase yields.
What is fertilizer?
In simple terms, fertilizer is plant food made from natural or industrially produced substances that growers apply to soil and plants to optimize growth. The nutrients in fertilizers may be beneficial to many different plants, including potted houseplants, flowers like roses and hydrangeas, and cannabis.
Why is fertilizer important for cannabis plants?
Essential plant nutrients present in fertilizers may help cannabis cultivators raise a healthier crop of marijuana plants with more abundant leaf growth and, eventually, flowers. If you want to grow big buds, the right cannabis fertilizer can help you reach that objective. Without a good fertilizer, the buds on marijuana plants may not reach their full growth potential. Further, marijuana grown with fertilizer will probably be healthier overall, which can translate to more pleasant and full-bodied flavor in the buds.
What nutrients do cannabis plants need?
A cannabis garden needs a combination of essential nutrients and trace, or micro, nutrients. The best marijuana plant food will offer a balance of a vital trio of nutrients.
The big three primary nutrients that marijuana plants need to grow are NPK — short for nitrogen, phosphorus, and potassium. NPK are the collective building blocks of any cannabis fertilizer, as well as any thriving marijuana plant. Cannabis plants also need carbon dioxide and oxygen, which they obtain through airflow, and hydrogen, which comes from water.
Marijuana plants also require secondary nutrients, which include sulfur, calcium, and magnesium.
Finally, there is a more expansive group of trace, or micro, nutrients that boost marijuana plant growth. These essential micronutrients include zinc, manganese, iron, boron, chloride, cobalt, molybdenum, and silicon, among others.
How and when should you fertilize cannabis plants?
Marijuana plants need different levels of nutrients depending on their growth stage. In general, marijuana fertilizer should be applied at least once weekly, along with an ample supply of pH-balanced water.
As a rule of thumb, the ideal pH balance for marijuana grown in soil ranges between 6.0 and 6.8. Hydro, or hydroponic, growers should keep their water pH in a range of 5.5 to 6.5. On average, marijuana plants need a gallon of water each day per pound of anticipated flower.
Plant growth is equally dependent on the work of fertilizers and nutrients. Here are some guidelines for applying fertilizer during different stages of growth.
- Seedling: Minimal or no fertilizer. You may want to wait until your plants have sprouted a few leaves before administering the first dose of primary NPK fertilizer.
- Vegetative: For Week 1, use an NPK ratio of 2:1:2 — that's two parts nitrogen to one part phosphorus to two parts potassium. By Week 7, consider increasing the NPK ratio to 10:5:7, followed by a 1:1:1 ratio in the late vegetative phase.
- Flowering: At this juncture, stop feeding nitrogen to the plants and focus on elevating the phosphorus and potassium levels. It is useful to fertilize plants during the early flowering stage but not as effective in the latter weeks after true buds have formed.
In addition to weekly feeding, marijuana plants require regular watering with pH-balanced water. As a rule of thumb, the ideal pH balance for marijuana grown in soil ranges between 6.0 and 6.8. Hydro, or hydroponic, growers should keep their water pH in a range from 5.5 to 6.5. On average, marijuana plants need a gallon of water each day per pound of anticipated flower.
For even better results, make sure to research the best feeding schedule according to the weed strain you are growing.
What is the best type of weed fertilizer?
If you want to grow an organic garden, choose a natural marijuana fertilizer containing the following materials:
- Worm castings
- "Good" bacteria and fungi
- Forest humus
- Fish meal
- Blood meal
- Bat guano
- Compost tea (aka a mix of the above elements, in addition to kelp meal and molasses, which maximize the benefits of the other ingredients)
- Biochar (aka a rich blend of carbon and charcoal)
Integrating these ingredients into regular soil can help you create a super soil with a diverse wealth of primary, secondary, and trace nutrients. While you can also purchase commercial fertilizers in liquid or powder form, natural materials often provide the most powerful nutrients.
One upside of synthetic fertilizers is that they tend to work faster than organic fertilizers. They may also be less time consuming and make a good choice for growers who prefer not to get their hands too dirty.
Bottom line on weed fertilizer
Using the right fertilizers and nutrients in the right quantities at the right time are essential to achieving an optimal cannabis grow. Ultimately, the best fertilizer for cannabis is the one that works for your schedule, budget, and level of desired effort. Growing cannabis requires a delicate balance of the right nutrients, so make sure you give your plants the attention they need and they will reward you with delicious, healthy buds.