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 Humboldts Secret Starter Kit Pack is a comprehensive fertilizer and nutrient system designed for both indoor and outdoor plants, including cannabis. This kit includes six different products: Base A & B, Golden Tree, Flower Stacker, Plant Enzymes, and CalMag & Iron, providing a wide range of nutrients necessary for optimal plant growth. The kit covers between 125 and 150 gallons of nutrient solution, making it suitable for larger gardens or multiple plants.

The liquid form ensures easy mixing and application, and the 1:1 mixing ratio simplifies the process for beginners. It is compatible with all grow mediums, including hydroponics, sand, gravel, and coco mix, providing versatility for various growing conditions. Additionally, it's made in the USA with high-quality ingredients, which is a plus for those looking for reliable and locally produced products.

This kit appears to be synthetic rather than organic, which might not appeal to users looking for purely organic options. Furthermore, the quick-release nature of liquid fertilizers means you might need to apply it more frequently compared to slow-release alternatives. This product is well-suited for those looking for a robust, easy-to-use nutrient system for their outdoor cannabis cultivation.

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.