How Does Fertilizer Grow Cannabis?


When you decide to grow cannabis, you have to ensure that the plants have proper nutrition and grow in the right environment, whether it is indoors or outdoors. Growing cannabis indoors is the better solution because you keep it safe from the elements, and temperature changes can impact your plants, and not in a good way either. You also must know what to feed your plants and learn about their nutritional needs during various stages of their growth. You know that you need to get fertilizer for your cannabis plants, but what does it do, and how do you use it?

Let’s focus on the micro and macronutrients and then zero in on how you should use your fertilizer to grow your cannabis plants. Different stages of growth will require various nutritional needs.

What Are The Cannabis Micro And Macronutrients?

When you grow cannabis, you know that they require three nutrients in substantial quantities: the macronutrients: nitrogen or N, phosphorous or P, and potassium or K. Those are the primary nutrients that keep your cannabis plants healthy and thriving. Therefore, you will see on any fertilizer that there will be an NPK label with different ratios. The ratios show that the higher the number next to the letter, the higher the nutritional value and concentration of that nutrient.

For instance, if you get fertilizer that says 5:5:10 on the label, then that means the value of nitrogen is five percent; the value of phosphorous is five percent, and the value of potassium is ten percent; which means that particular fertilizer has the highest concentration of potassium.

However, your cannabis plants require more than NPK to survive. They need calcium to develop cell walls, magnesium for carbohydrate metabolism and photosynthesis, and sulfur which helps the plant produce different proteins, amino acids, enzymes, vitamins, and chlorophyll.

The plants require smaller amounts of copper, zinc, boron, manganese, chlorine, and molybdenum, micronutrients. You also want to get the correct type of fertilizer for your plants based on how you grow them. For example, if you use hydroponics that involve no soil for growing them, you want to use fertilizers designed for hydroponics.

There are also fertilizer supplements as they contain low ratios of NPK, which are to add more of the nutrients if the plant requires them. The essential thing is that you feed your cannabis plants the correct ratio of fertilizer and nutrients based on their growth stage. That means you will need to know when to start giving your cannabis plants fertilizer immediately. So, let’s talk about the various stages of growth and the nutritional needs they require for those stages.

What Are The Various Stages Of Cannabis Growth And Nutritional Needs For Those Stages?

The first stage of the growth of the cannabis plant is the seedling stage, and they receive their nutrients from the seed, and their root systems and leaves begin to develop. You do not want to feed your seedlings fertilizer before three weeks of development as they don’t need it. However, they require an environment that is humid and warm.

When your seedling is around three to four weeks old, it will have about three to four leaves as they enter the vegetative stage—that si when you can begin feeding the plant. However, provide your plants very slowly and only give them small amounts of NPK, which can be as low as the 2:1:2 ratio as soon as they enter the vegetative stage. If you give them too many nutrients, they will burn. You can safely give them 4:2:3 fertilizer after the first week is into the vegetative stage as it can supercharge their growth.

However, by the time your plants are around six weeks into their growth which is the mid-vegetative stage, you can give them the 10:10:10 fertilizer, which will help support their rapid growth spurt. You may also want to talk to weed-growing experts about advice on that, too, if you are unsure.

The robust nitrogen levels will help your plants develop large foliage and an abundance of buds, as at this point, the plant will enter its flowering stage. However, when the plant enters the flowering stage, you will give it less nitrogen but more potassium. Potassium is essential for growing large flowers with plenty of resin where the THC resides. Therefore, you will want to provide a lower ratio fertilizer and potentially potassium supplements for the first two weeks of the flowering stage. After that, you can feed your plants higher nutrients while giving the plants more potassium, such as a 5:10:15 fertilizer.

During the last weeks of the flowering stage before harvesting, you will want to lower the nutrient levels to transition to the harvesting point but keep giving it more potassium. Ideally, the 5:5:10 fertilizer may be ideal with some supplements. Now that you know what to give your plants, you will learn how to feed them.

How Often Should You Feed Your Plants?

There is no one-size-fits-all approach to how often and what to give your plants as fertilizer brands provide you with feed charts. However, a feed chart will usually involve a 12 to 13-week growing cycle and will emphasize what nutrients and ratio of nutrients to feed your plants. Most of the time, you will provide your plants once a week once you can start feeding them. Additionally, fertilizer brands will instruct you on how to feed them by giving you a ratio of feed to water which will be either in gallons or liters.

When you prepare your water, you will want to ensure the temperature is close to 72 Fahrenheit or 22 Celcius and follow the instructions carefully to add the nutrients to the water. Then stir it well. You will want your pH levels to be ideal too, and then you can begin feeding them.

Recent and relevant information about the subject:

Organic Fertilization in Cannabis Cultivation: Recent trends in cannabis cultivation emphasize the use of organic fertilizers. These natural options, such as compost teas and organic nutrient blends, not only provide essential nutrients but also enhance soil health. Organic fertilization fosters a rich microbiome, crucial for sustainable cultivation practices.

The Environmental Perspective: Modern cannabis cultivation is increasingly focusing on the environmental impact of fertilizers. Sustainable practices, including the use of eco-friendly fertilizers, minimize ecological footprints, promoting greener cultivation methods.

Hydroponics Innovations: The advancement in hydroponic nutrient solutions is revolutionizing cannabis cultivation. Tailored nutrient solutions designed for hydroponic systems optimize plant growth and health, offering an efficient alternative to traditional soil-based cultivation.

Research Breakthroughs: Recent research delves into the unique nutritional needs of different cannabis strains. This knowledge aids in developing more precise fertilization strategies, enhancing both yield and quality.

Insights from Commercial Growers: Incorporating case studies from commercial cannabis growers provides practical insights into the application of these advanced fertilization techniques. Their experiences offer valuable lessons for both novice and experienced cultivators.


When you decide to grow cannabis‘, you must know what ideal temperature and environment you need to grow your plants for them to thrive. You also need to feed them the correct amount of nutrients and know what fertilizer to provide your plants. Follow the instructions carefully on whatever fertilizer brand you purchase so you can grow a healthy plant that will provide you with some healthy and large buds that will host a lot of resin that contains THC. If you give your plants the wrong amount of nutrients, it could burn them, and that is not what you want to happen.