m0useanswered grow question 3 years ago I would wait a bit. Hardly any brown pistils on that plant.
The directions for use are this:
Mix 2 ml per liter (0.4 tsp per quart) during weeks 5 and 6, or the last 2 weeks of your flowering phase.
I feel you have a another week or two before its ready for overdrive and enters late stage flower.
Good Luck!