Can compost tea replace fertilizer?

While compost tea has many benefits, it cannot fully replace conventional fertilizers in most gardens. Compost tea will provide beneficial microbes that increase soil biology and nutrient uptake, but it does not provide sufficient nitrogen, phosphorus, and potassium needed for heavy feeding plants. I know this because my tomatoes exhibited signs of deficiencies, even after I applied compost tea regularly. The deficiency issues were completely resolved with the use of organic fertilizers.

Soil testing establishes the appropriate levels of supplementation. I conduct tests once a year, typically in the spring, for NPK and micronutrients. For nitrogen-hungry crops, such as corn, I will add fish emulsion fertilizer with a brew of teas. For soils deficient in phosphorus, I use rock phosphate as a supplement. This combination yielded terrific results with minimal waste.

The timing of applications allows maximum benefits. Apply tea before applying fertilizer to wake up and establish soil microbes. Wait 48 hours before adding granular nutrients to allow for the microbes to develop. My schedule includes tea every two weeks and organic fertilizer about once a month, as growth is highest during this period. Reduce both applications during dormancy.

Watch your plants' reactions to fine-tune your methods. Yellowing leaves on lower plants indicate a nitrogen deficiency, which can be corrected with a fertilizer. Slow growth, even with tea, can indicate a phosphorus deficiency. I keep a journal of plant responses to mixtures, ensuring I know which mixtures to use and when to apply them. This way, I don't over-fertilize but still give them what they need.

Read the full article: Compost Tea Brewing: The Ultimate Guide