BudXsanswered grow question 5 years ago I love the PK boosters. Adds serious weight IMO. Dont put them into the mix until week 4 of flower, and only start at 25% of the recommended dose. Add to every feed and increase until 100% dose or whatever the plants can handle. Beware though>> This is serious stuff if its overdosed. It will burn plants to a crisp if you are not careful. You will want to taper off about 10 days from harvest, and flush well before chopping. Always use this stuff with other nutes. When you are at the end phase of flower and you've tapered off your Nitrogen, you must taper the PK as well. If you dont you are sure to suffer a burn. If you see a burn, treat it right away.