trichlone, 28 days at the maximum.
mineral nutrients like HESI goes way faster. Try not to feed your hydro for a month and see what happens.
You could fertilize up to harvest, but why?
It won't help you.
If your using soil you should do a flush at a week before harvest to remove EXCESS salts (from overfertilizing). If you'r a light feeder you should flush with less water.
Then for the last week you should use straight water. (or with molasses or a flushing agent. I use none)
In coco you should flush for the last 4-5 days in the same manner.
In hydro you should flush for the last 3-4 days.
A longer flush will remove the fertilizer taste but might decrease the yield as you'r denying the plant from nutrients for too long.
For the last 2-3 days you should turn off the lights (if possible) and give the plants straight darkness.
Not only it will save you some $$$, it will make the buds rippen faster. Or at least look like that way.
Giving your plants light for the last 2-3 days will not help with anything.
You could get a harvest without a flush and with 12\12 until harvest, but why?
not only it will taste better and look better, it doesn't requier any effort on your behalf!
And rest assured - your yield will not be compremised.
In soil I flush 18 days before harvest and give my plants straight water.
In coco\perlite I do the flush a week before the harvest.
I shut the lights down for 3-4 days before harvest.
It might lower my yield a bit but it saves me a lot of money and I think it gives me a better product as well.
There is so much wrong here... where to start?!
I wont even talk about the parts where you contradict yourself regarding yield.
2/3 days darkness? benefits are disputed 50/50 & to most growers who dont have unlimited space, tents, fans, filters... leaving your plant in the dark for this long at its most ripest in an uncrontroled enviroment, is an open invitation to bud rot. Daft!
If you flush to remove salts from over-fertilizing then YOU ARE FEEDING THE PLANTS WRONG by definition!
fertilizer taste?!?! what in the name of all things holy are you talking about? If you over fert, the smoke will have a harsher taste , the bud will also crackle more when burning, possibly carinogenic if you are crazy enough to smoke weed grown on chemicals. But you wont be able to taste the fertilizer, no more than you will with strawberries, tomatoes peppers etc that are grown in pig shit. Daft again.
Shouldn't common sense alone tell you that deviating from how the plant naturally grows can only be detrimental to the end result? In nature there is no "flush". Experiments conducted by real scientists, prove this beyond any doubt.
Its mumbo jumbo like this that keeps the myths alive & the nutrient makers in $$ heaven.