What is Flushing and When to Flush Plants?
When you flush a plant, you feed it only pH balanced water and no nutrients or fertilizers for a period of time. Flushing is especially important prior to harvesting. Nutrient residues can accumulate in buds and will give the flower an off-flavor when dried and used. Plants naturally draw nutrients to their flowers in preparation for producing seeds. If you are harvesting for flower and not seed, you will have to correct for the plant's natural tendencies by flushing. When the plant is fed only pure water in place of the nutrients, the stored minerals will be pushed out of the buds and utilized in the rest plant.
When to Flush Plants?
Color changes in leaves leading up to harvest will signal that plants are reaching full maturity. If you look at the trichomes under a loop (magnifier), they should be 10% to 20% brown. That is the sign that it is a good time to start flushing plants.
How Long to Flush For?
It takes about five to seven days of flushing to remove nutrient residues from the ripe buds. Ultimately flush time will be influenced by your growth media. Five to six days of flushing is usually sufficient for a mix like peat, coco coir, and perlite, but if your growth medium likes to hold on to nutrients you may need to flush for longer.
Flushing for Nutrient Lockout
Flushing is also useful if plants are experiencing nutrient issues like nutrient lockout.