That's not really flushing, that would be leaching. Flushing is pouring copious amounts of water thru the soil to flush the fertilizers out of the soil. Using just water the last week won't harm much since there will be nutrients still left in the soil. But it isn't necessary either, it's a myth that you can leach the chemicals out of the buds imo. I've done both, feed up until the end and also use just plain water the last two weeks, there is no detectable difference in the finished product. So now I just make sure that they have enough food to stay healthy until the end.
