hey konagirl,
its all pretty simple... there are ways to flush with just water or whatever, but i prefer to use a flushing agent like Botanicare Clearex (or AN Final Phase, or many others). it will leach the salts and other unused nutrients out of your grow medium. basically you just mix some up, and since you are in soil, you would just continue pouring it through the soil until you are achieving 80-90% run-off. some people do it twice to make sure they get everything (a second time with a fresh batch). ideally you would want to do it close to end of grow, not too soon cuz you'll take all the bloom nutrients it needs to finish, and not too late or you wont flush it all out... i would say for you, flush a week before you cut them down. after the flush you would water as needed with plain water. if you get some Clearex or whatever too it will have mixing instructions on the bottle. probably about $10-12 for Clearex or alternatives. also for next grow, some growers flush their veg nutes out before they flip the switch on their lights to flower, that way the plant is getting fresh bloom nutes and it takes away a lot of the worries about lockout or nute burn/imbalance and should help stimulate the switch to flower quicker. some people flush every 2 feeding cycles. i think thats a bit much personally... once before flower, and once/twice at end of flower is pretty good i think... just my $0.02.........
cheers sexy mamasita hope this helps hahahaa woot!%
mister bond