If you are using COM Stonington blend soil, why not just stick to using COM when you flower them. To top dress for flower, add 1 teaspoon of Stonington Blend Plant Food for each (1) gallon of soil in your pot. For example, if you are using a 5 gallon pot, you would top dress with 5 teaspoons or 1 1/3 tablespoons of Stonington Blend Plant Food to top dress a 5 gallon pot, then you would also add 1/2 tablespoon of COM fish bone meal for each (1) gallon of soil in your pot. And just adding those (2) amendment at around week (2) of flower will get your plants through to harvest with just water and a bit of Epsom salt!