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 Farmer’s Secret Fruit & Bloom Booster Fertilizer is designed to enhance flowering and yield across various plant types, including cannabis, making it a versatile option for outdoor gardeners. Its super concentrated formula means you only need a small amount (1 teaspoon per 2 gallons of water), which can be convenient and cost-effective over time.

This liquid fertilizer is easy to use—simply dilute with water and apply during regular watering intervals every 2-4 weeks. Made in the USA, it is trusted by many gardeners.

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.