PreHarvest Flush, 3 times water or just regular PH water?

[ksmirov]

So Im past 7 weeks of flowering and my plants look ready for 2 week preharvest flush. Why do some people do 3x the size of the container flush and others just water with regular water ph?

 

[justnuts]

3x size of container flush = when you want to flush out residue salts from the pot. Mainly performed mid flowering or sometimes during veg when nute lockout occurs.

Pre-harvest flush is different. You use plain water (not PHed) to 'flush' the chemicals out of the buds. If properly done, at this stage the plant will use salt deposits in leaves and your leaves should turn yellow (or purple if cooler temps are used!)
You only need to do this for about a week.

For pre-harvest flush, 2 weeks is too long and you will affect the final burst of growth. Alternatively you could start reducing your feed slowly until the last 5 days, where you can start with only plain water (not PHed).

Personally I use a flush nutrient (no PHed) for 5 days, and then 3 days plain water only.