Hi stevie, I grow hydro but I just started some seeds in peat pots for my veg. garden and the post became moldy so I sprayed them and it killed the mold. Serenade is some type of microbe derivative that interrupts the molds life cycle. I've soaked my plants with it with no problems. Make sure you keep your fans on and RH down when you get into flowering. I discovered Serenade after I discovered bud rot on my plants late in the flowering phase.