I've always been told to flush my plants 2 weeks before harvest and I've done that. My last grow I fertilized up to the last 2 days before harvest and my grow was the most potent to date but with only 6 grows under my belt that isn't saying much. I've read so many differing options on this. To me it seems flushing 2 weeks even one week before harvest denies the plants of much needed nutrients. Does anyone have "the answer" to what seems to be a ago old question? For now I'm going to fertilize up to the end unless someone has proof otherwise it's best to flush.

Flushing (in my opinion and experience) varies according to several variables. If you are in "organic" soil and feed organically then flushing is meaningless. If you are in hydro, using synthetic nutes, then flushing is important in some instances, depending on the medium that you are in and what kind of nutrients you are using. If you are in a hydro setup and growing a lite feeding plant with mild nute all the way through then flushing is most likely unnecessary. If you are growing nutrient hogs in a soilless mixture, and feed heavy, then flushing will be necessary.

I grow in coco/hydro and I have varying plants. I always flush at the beginning of flowering(end of 3rd week when I switch to full bloom nutes) and then feed up to the last week where I cut off the nutes and only top up with straight water. I personally don't see where nutrients in the medium will make it up through the plants to serve the plants' needs during the last 4-6 days, so I don't waste nutrients on that week and just allow the plants to use up what they have in the soil and in their systems. I have found that by flushing when I do that it cleans out any buildup in the medium so that when they get toward the end of flowering, I don't have any issues with toxic builup :-)

there's no 'answer' been many discussions about this, and we never come to a soild answer. people do what works for them.
myself, i'll always feed plain water at the end.

I assume, much like almost everything else, that these guidelines (2, 1 week) refer to "soil" and a guide # for hydroponics is different.
as a N00b hydro grower could someone put down some hydro experience #'s too.


from my other hobby/forum, we use "YMMV" (Your Mileage May Vary) when throwing out #'s that have no hard definition.
makes it easier to say: I flush for 8 days YMMV. That way everyone takes the # with a grain of salt and knows that it might not work for them.

I never stop feeding my Girls. Never seen the reason,,but to each his own.

I do not flush period. Flushing imo is more to correct a growers mistake.

I feed my Veggies right up to the time im pulling them off the vines and my Veggies taste really nice. My Tomatoes are sweet like candy. So I dont get the flush thingy,,even before I went Organic.
I flushed a grow once in Florida and could not tell the difference between it and the other grows,,,and they were the same Clones. After a good cure,,they tasted exactly the same.

i have ran a flush at 3rd week of flower and for last few days.. Same strain no flush no rinse at the end.. I didnt notice a difference so being cheapskate I kept with the flush...two less resi tanks to throw away the nutes in...end of year doing a tray a month was 24 tanks...figured was worth to hold on to nutes...
my two cents......

I also never flush my plants unless I have a problem. I found like you did--that when I fed up until the end that the buds were larger, denser, and more potent. To my thinking is like this: You are asking your plants to put on a whole lot of trichs and weight that last 2 weeks, so how does slowly starving your plant help it do this? It doesn't. And I can guarantee you that no one can tell the difference after a good cure. I don't know how the flushing thing even got started--we don't flush any other plants we grow--but I personally have found that it flushing was detrimental and did not make one bit of difference in the way a plant tasted or smoked after cure.

in my exp the advanced nutrient calculator is about 3x as strong as needed. They also sell flush products. I think the whole flushing thig is for us to buy more of their product...feeding to the end is critical..
As a side question...in hydro how long can you run water in the middle of a run before plants would show nute deficiency....there would be some buildup in the medium..and how long does it take for the root absorbtion and uptake through the plant? Im not a scholar so is this instantaneous during lites on when they fire up photosynthesis per say?? or does it take some days to uptake through and through??
think i will do some reading ...

I flush about a week before harvest because I want to smoke as few chemicals as possible, that is why I quit smoking. I could not taste the chemicals in my tobacco either but I know they are in there. I have 3 gallons of dirt ,it takes almost 9 gallons to get my tds down to regular water level. I must say the potency increase sounds tempting tho.

how could the potency increase from 1 or 2 extra feedings? i really don't get that.
also, i notice everyone keeps saying 'after a good cure you can't tell' .. so what about a bad/no cure?

honestly tossed up, i know you guys aren't lying and truly believe this.. but my experiences are far different from yours (enough so, that i wouldn't even temp feeding synthetics all the way to harvest, again. just to test it)

flushing has been on my mind also. I was taught somewhere to flush. lol But it would do me a great service not to flush. a whole lot of less work. When I was at Mandelas web sight to read how they germinated seeds I read that they don't recommend flushing, and they give their reasons why. From what others say here as well I think I'll adopt the no flushing guideline. I grow organic as well so I'm glad there's no need. And sounds like a plus more nutes to help the flowers grow larger. Thanks guys.

In the words of Lucas, Flushing is for people who over feed.

I also never flush unless it's to correct an error I've made. But, I also don't feed anything but water the last week or so as the plants don't usually need it, beyond 3ml/gal GroTek Heavy Bloom for resin production