General Hydroponics ProRelease Field Formula 20-7-20 is a blend of coated and uncoated granulated fertilizers designed for high value field grown crops like hemp and other aromatherapeutic herbs. Apply at the start of your season and watch your crops thrive. Feeds for up to 4 months*. *will vary based on soil needs, planting density, climate, crop, media, irrigation or rainfall amount and especially other nutrient usages.