Feed every other watering, and in normal situations that results in approximately twice a week. The plants can't uptake all of the nutes given in a feeding on a single watering cycle, but if you follow up every other time with water pH adjusted to 6.3, it reactivates any leftover nutes and gives them a second shot into the plant. This keeps the soil nice and clean, and allows the plant to take it a little easier on the second pass.
