Growth nutrients

Hi there, that depends on what your growing medium is? If you're using pre-fertilized soil, then maybe you don't need anything for a few weeks, while on the other hand if you're in hydro, then you need nutrients right away. Also what do you mean with "growth stimulator"? Do you want something like a PK booster during the blooming phase, or do you mean nutrients in general for the vegetative phase? There's not much information or explanation on your question, so it's a bit difficult to give precise answers. I use GHE (the European part from General Hydroponics, which has not been taken over by Scotts/Miracle grow) for my regular nutrients, and then Advanced Nutrients, for my additives during flowering. With both of them i measure my EC and do not blindly trust the amounts that they mention on the bottles, as in that way i would have overfertilized them to death already. They get what's being measured what they need instead. happy growing!