10 Best Outdoor Cannabis Fertilizer 2025 in the United States

The FoxFarm Fertilizer Soil Trio Liquid Nutrient kit includes three products: Grow Big, Big Bloom, and Tiger Bloom, each designed to support different stages of plant growth. This makes it a versatile option for outdoor cannabis growers. One of its strengths is its organic formulation, particularly Big Bloom, which is both OMRI Listed and registered as a CDFA Organic Input Material. This can be beneficial for those looking to grow organically.

The liquid form ensures easy application and quick absorption by plants, which is useful for seeing faster results. Additionally, the included Twin Canaries Conversion Chart helps users mix the nutrients accurately, which can be a great help for beginners. The pack's phosphorus-rich Tiger Bloom is particularly good for encouraging flower and bud development, which is crucial for cannabis plants.

This product is best suited for those who want an easy-to-use, organic option with a focus on both vegetative and flowering stages, although it may require additional slow-release nutrients for long-term feeding.

The VIVOSUN Liquid Nutrients Base A & B Bundle is a two-part liquid fertilizer designed to support all stages of plant growth, from vegetative to flowering, making it suitable for outdoor cannabis cultivation. It provides a balanced mix of essential macronutrients like nitrogen, phosphorus, potassium, calcium, and magnesium, along with important micronutrients, which helps prevent nutrient deficiencies commonly seen in cannabis plants.

This nutrient formula is synthetic and fully water soluble, allowing for quick nutrient availability and easy absorption by plants. It is compatible with various growing methods, including soil, hydroponics, aquaponics, and coco coir, offering flexibility for different growing setups. Additionally, it helps stabilize the pH level of the nutrient solution, an important factor for optimal nutrient uptake. A key convenience is that it requires only two bottles (Base A and Base B), simplifying feeding routines without complicated nutrient mixing plans.

The two parts must be diluted separately and never mixed in concentrated form to avoid nutrient lockout or chemical reactions. Although the product is not organic, its comprehensive nutrient profile and ease of use make it a solid choice for growers seeking reliable, consistent feeding for outdoor cannabis plants. Since it may lack slow-release properties, it is best applied regularly with watering to maintain nutrient levels.

FoxFarm Big Bloom Plant Food is a versatile liquid fertilizer designed for both indoor and outdoor plants, including flowers, fruits, and vegetables. For outdoor cannabis cultivation, it has a very low NPK ratio of 0.01-0.03-0.7, which suggests that it's more of a supplement rather than a primary nutrient source. This low ratio is beneficial for young plants or those in the blooming stage, as it promotes flower growth without risking nutrient burn.

The fertilizer is organic, made with ingredients like earthworm castings and bat guano, which are great for enriching the soil naturally and promoting microbial activity. This can be a plus for growers looking to maintain organic growing practices. Additionally, it includes micronutrients that support plant health and development. The formula is quick-release, meaning plants can absorb the nutrients faster, which is useful for addressing deficiencies promptly.

The pH compatibility is not specified, so users may need to monitor and adjust soil pH to ensure optimal nutrient uptake. The easy application process, where the concentrate is mixed with water, makes this product user-friendly, even for beginners. In summary, FoxFarm Big Bloom is a good supplementary organic fertilizer for outdoor cannabis, particularly useful for blooming stages, but may need to be used alongside other fertilizers to ensure a complete nutrient profile.