How long should I flush?

I'm a 2-3 weeks from harvest and I'm planning on flushing before I chop. How long should I flush? I seem to remember seeing somewhere that I should flush for 2 weeks but I've seen 1 week in other posts. What do you think?

I flush for a week in my dwc, i drain the res and replace with clean water.

JP

Thanks dude. I'm growing in soil under CFLs. Should it be any different?

are you in soil? It might take longer for soil. im a hydro grower

The lights make no difference to the flush

JP

Soil takes quite a bit longer to flush, typically I flush sativa's for 2 and 1/2 3 weeks and indicas for 1 and 1/2 to 2 and 1/2. I flush sativas for longer because they typically have a much longer flowering period and more available nutrients in the soil and in the foliage for the last few weeks than the indica. But thats my experience.