You shouldnt need to feed at all from March- August. This is the period when the bees will do their thing and make you a crop. Feeding is done only in the spring on very weak colonies or in the fall ( starting end of September ) after you take all the honey and need to replace their stores for winter. Feeding any other time, the bees dont need to make honey as you are providing them food in house, and any honey in your hives is just stored syrup. Depending where you live makes a difference, if there are no spring flower sources you'll never make honey.
I'm in Harrisburg, and i still have clover in the yard. Look around, do you see any clover? If no clover, the dearth started. Make sure bees have something to eat until end of August.