how to use molasses as a fertilizer blackstrap molasses the same kind used to sweeten food stimulate microorganisms and contain minerals such as carbon sulfur potash and iron for these reasons some gardeners mix the sweetener with liquid fertilizer to boost soil according to Native Plant Society of Texas news liquid molasses fertilizer when mixed with compost tea and used in conjunction with orange oil is effective in eliminating fire ants from lawns and gardens things you'll need unhhhh sulfur dragstrip molasses liquid fertilizer bucket sprayer combine one two three tablespoons molasses with one gallon liquid fertilizer in a bucket use commercial liquid fertilizer or a homemade fertilizer such as compost tea or alfalfa meal tea transfer the solution to a garden sprayer spray the fertilizer evenly at a rate of two to four quarts per acre two fertilized soil spray at a rate of one pint per acre to fertilize foliage on broadleaf plants grasses or grains