I don't flush plants that are in the ground. I don't know how one would do that without an extreme amount of water and in California, that would get attention because of the drought. I don't bother to flush the few plants in containers, I simply stop fertilizing them (in-ground, too) two to three weeks before the projected harvest time and water only. Here at 38 degrees N, that usually will be the end of September because the average harvest date is mid-October. However, I have two strains that will be harvested earlier and one that will go to Halloween, so one size does not fit all.