How come you flush? You grow in soil. Its not necessary.
Flushing is a finishing process at the end of hydro grows. It involves drenching the pot with more water than usual to change the gradient within the leaves so the plant will give up its salts. The idea being that it will affect the buds taste and how it burns.
I've only ever grown in soil. As close to organic as I can get.
If you wanna try sometime not flushing one plant and see if it makes a difference.
This is gonna be a long, general info post, Just a heads up. As politely as I can, as I don't want to assume anything that may have come from a miscommunication, I have to clarify your advice on flushing not being required for soil as only a half-truth. If he was to use super-soil (or amended) and only go organic, yes, you would be correct. He stated he uses a 50/50 perlite mix though. If he uses basically any fertilizer aside from compost-teas and such, he's going to need to flush.
Salts build up in the soil from almost all popular commercial cannabis soil ferts. There is a lot of organic stuff in them, but plenty of nutrient salts, too. So if you don't flush, and just stop fertilizing, the plants are going to continuously uptake on the nutrient salts. In the same form they come in the bottle. They are already broken down to be immediately absorbed by the roots. Not long after that, those chemicals are in the bud. It's their natural end-of-life, they aren't even looking for more nutrients at that point in the wild. It's either pollinated by now, or not...
With that said, if anything, it takes much longer to flush a soil plant than it does a hydro plant. I'd say 2 weeks, 1 week at least, depending on watering-style, amount allowed to drain, medium composition, container size, etc. (this is for pre-harvest, not remedy)
To the OP: I wanted to confirm what I just said, and came across this at
http://www.ilovegrowingmarijuana.com/flushing-marijuana-plants/ :
"Make sure you flush your marijuana plants when the harvest window is open. The timing also varies according to your grow medium and setup. For example, people who are growing their marijuana plants in amended soil should not flush at all, while people growing their plants in soil should flush them several weeks (1-2 or more) before the harvest. Coco growers should flush their plants about a week before harvest, while other hydroponics growers should only flush for a few days."
I just wanted to clarify that because it would be super-easy for a beginner to read your thread and misinterpret it and end up with less-than-desirable bud. On the other hand, this topic has never been fully agreed upon, always been controversial between growers. Many times, people don't understand the difference between pre-harvest-flushing and flushing as a diagnostic method for a sick plant. There isn't a lot of cons to flushing that have been overwhelmingly verified that makes enough of a difference for people to stop flushing. The pretty colors of the leaves towards the end are worth it on its own to me.
Everyone has their own industry secret that gets them "monster yields, taste, smell, etc". I read one post once and the grower was trying to say that keeping a male plant next to females, but sealed off as to not pollinate the females, makes the bud stronger, she said. Seriously, some woman had a male plant spreading pollen everywhere and just 1/2 inch of plywood away are flowering females because of bad advice. You gotta do your own research, is what it comes down to. Asking about it IS research, but always verify via another source anything you read on any forum, 'cause while it's a great community, many people here are beginners and will have beginner advice, which can go one way or the other. I have one cannabis grow under my belt but I've been studying horticulture and growing legal agriculture for over 15 years now. I come here to mostly spread good advice and I'll ask the obvious question now and then.
Sorry for all the typing. This hobby will do that to you. Hard to talk about one thing without going in to other stuff.
Happy growing!