I JUST FLUSH FOR 2-3 WATERINGS BEFORE CUTTING. NO WAY TO TELL BEFORE HAND HOW MANY WEEKS TILL KILLING. DON'T FLUSH EVERY DAY FOR THAT MANY DAYS,,, JUST WHEN YOU WATER FOR THE LAST FEW DAYS,, JUST GIVE EM CLEAN WATER. LET EM USE THEM WATER LEAVES YOU LEFT GROWING.

GOOD LUCK