my mentors all do it so I would have too say yes, apparently use liquid first, and last three weeks use powder, but more is NOT better follow the amounts given on the package as tho it is scripture cheers
I've used the liquid/powder protocol GH recommends, and found that 1/4tsp of the powder, NOT 1/2 tsp per gallon is a better dosage. I've read that powdered KoolBloom at the recommended dose causes hermies, but at that late in flowering it shouldn't be too damaging.