You do not need to stop feeding your plants two weeks before harvest. – Jim
To flush or not to flush...
Ok, I will preference with the notion that I hate this topic, but it must be addressed. A lot of growers recommend only feeding clean water with no nutrients the last two weeks before harvest. The thought is that this creates a smoother, natural flavor when smoking because there isn’t nutrient chemicals or chlorophyll in the smoke. I say show me the proof! I’m not sure where this idea came from, but farmers of non-cannabis plants absolutely don’t do this.
Some will scream “But they are growing outside it’s different!” How? And yes I know about salt buildup (this shouldn’t be a thing if you flushed right before flowering), and yes I know that it supposedly breaks down chlorophyll. I will agree that chlorophyll creates a harsh smoke, but I also know that it breaks down anyways with a good cure. Tobacco growers cure for this reason as well.
It's very common for cannabis plants to put on a lot of weight near harvest. I just don’t think it’s a good idea to withhold “food” during a period when they need a good amount of energy. Flushing will do nothing to rid the nutrients that the plant already has in tissue. And again no gardener of any other plant flushes before harvest.
Even if you can come up with a scientific argument that shows flushing is good, you still have no peer-reviewed studies to back it up. I’d much rather wait an extra week when curing to completely break down all the chlorophyll than jeopardize my yield by starting the process early in flowering.