Best growth fertilizers for marijuana plants

Marijuana plants use up a lot of nutrients during their vital cycle, which starts with their rooting and ends with the flowering period. For this reason, fertilizers are key to make sure that the plants grow strong and healthy, which is crucial for the structure, size and flavor of their buds. However, it is quite common to be overwhelmed by the amount of fertilizers in the market and wonder which are the best growth fertilizers for cannabis plants.

What is a growth fertilizer?

A fertilizer is a product that provides plants with the necessary micro and macro nutrients to grow properly, which affects their vital cycles directly.

In the case of cannabis, the growth phase starts very soon after a short rooting period and it is then when the plant puts all of its energy into growing and creating stems and leaves. This process is essential for the final result because the bigger and stronger the plants get, the more energy they’ll have to produce great quality buds.

Growth fertilizers are very important to provide plants with the necessary nutrients, always using only the dose recommended by the manufacturer as over fertilization can be fatal for the plants. Equilibrium is necessary in order to avoid nutrient excesses or deficiencies.

The importance of NPK during plant’s growth

NPK stands for Nitrogen (N), phosphorus (P) and potassium (K). These three basic elements  for the proper development of plants, cannabis included, therefore, it’s important to emphasize on its distribution.

During the growth period, plants need more nitrogen than phosphorus and potassium because it is the most needed element to create roots, stems and leaves. Providing cannabis plants with fertilizers rich in these nutrients guarantee a good quality yield.

Available types of marijuana growth fertilizers

1. Organic

An organic fertilizer is the one that uses natural ingredients, such as seaweed, earthworms, animal and vegetable remains, etc…Feeding the plants with organic fertilizers is environmentally friendly and widens the amount of resources, which improves the final flavors. However, the plant takes longer to absorb all the nutrients and the process is less specific than using chemical fertilizers, which is a bit inconvenient.

2. Chemicals

These products have the exact amount of nutrients that plants need, therefore, it is very easy to control their growth. They are also easier and faster to absorb, which maximizes the yield. These qualities along with its affordable price make it understandably the most used type of fertilizer.

On the other hand, it is easy enough to over fertilize the plant if the dose provided is not correct, which can delay the yield and even ruin the crop. Unfortunately, the heavy metals present in these types of fertilizers are harmful for the human body, therefore, the roots need to be flush at the end of the process to remove excess chemicals and make sure that the flavors don’t have a negative impact on the flowers. 

3. Bio-minerals

Bio-mineral fertilizers coincide in their composition with chemical ones, as both include mineral properties, however, bio-mineral fertilizers don’t use chemical processes to make them, which makes them less harmful for humans. 

However, as these products still have heavy metals, it’s important to flush the roots before harvesting the yield. These fertilizers are very easy to absorb and promote a fast, healthy and strong growth.

Which are the best growth fertilizers for cannabis plants?

Crecimiento Boom, by Boom Nutrients

Crecimiento Boom, by Boom Nutrients is an excellent bio-mineral growth fertilizer for marijuana plants. Its NPK proportion is 11-5-6, which guarantees the necessary nitrogen for stems and leaves to grow strong and healthy. Suitable for indoor and outdoor grows.

Results are visible after only two uses, which shows the potency of this fertilizer that features a refined formulation that enables the plant to benefit from the nutrients without suffering an over fertilization. 

Combine with other Boom Nutrients products to make the most out of the crop

Other interesting facts:

• It improves plants’ stress management
• Sorts out nutritional deficiencies when sprayed onto the plant.
• Increases plant’s photosynthesis capacity
• Apply once a week, alternating normal irrigations with others with the product included.

Top Veg, by Top Crop

In second place, we have Top Veg by Top Crop, which is also a good option to ensure marijuana plants’ proper growth. This organic-mineral growth fertilizer is rich in micro and macro nutrients; guaranteeing a fast and easy assimilation that improves plants’ defenses during the vegetative period.

Its NPK distribution is 9-4-8, slightly lower than Crecimiento Boom but richer in potassium. It also features some secondary nutrients, such as magnesium, which improves sunlight absorption, and humic and fulvic acids, which boost plants’ development, especially the roots.

Other interesting facts:

• Apart from its NPK distribution, it contains 1% of magnesium, 3.9% of humic acids and 2% of fulvic acids.
• Apply once a week.
• Combine this fertilizer with other growth stimulators to boost the properties of the plant. 

Alga Grow, by Plagron

In third position we have Alga Grow, by Plagron fertilizers. This is the only organic fertilizer of the list, therefore its ingredients are fully natural. Its rich nutrient combination includes seaweed extract, beetroot juice and amino acids; on the other hand, its NPK content (4-2-4) is kind of poor in comparison to other bio-mineral options.

However, this growth fertilizer is eco-friendly and improves the structure of the soil. We recommend combining it with a root fertilizer or other stimulators to boost the results.

Other interesting facts:

• Stabilizes the pH of the soil.
• Suitable for organic farming (CU certified).
• Not suitable for hydroponic grows.

Grotek Growth Booster

Grotek Growth Booster is a highly concentrated growth stimulator designed to boost the vegetative phase of cannabis plants from the early stages. Its NPK 16-40-0 formula delivers a strong supply of phosphorus and nitrogen, promoting strong roots, sturdy stems, and large leaves to prepare plants for a more abundant and uniform flowering phase.

Results are visible quickly, as a single application during the growth phase significantly improves overall plant vigor and nutrient uptake. Compatible with soil, coco, or hydroponic systems, Growth Booster supports balanced development without the risk of over-fertilization.

Other key features:

• Promotes a strong and healthy root system, essential for supporting vegetative growth and later flowering.
• Increases plant density and vigor, producing large leaves and resilient stems.
• Single application per cycle: 1 g of Growth Booster per 10 liters of water.
• Not recommended to mix with other fertilizers or stimulators in the same application.