Monterey Garden Insect Spray 

This is the best answer for thrips or gnats in any indoor or outdoor garden! A little of this concentrate goes a long way and will virtually eliminate an active thrip or gnat infestation with only one or two applications. 

Monterey Garden Insect Spray kills insect eggs that are laid on plant stems and leaves using Spinosad, a naturally-occurring soil bacterium.

Application Rate: Use four tablespoons of concentrated Monterey Garden Insect Spray to one gallon of water. Apply as a foliar spray, making sure to also saturate the plant stems and the undersides of the leaves.

This fast-acting insecticide is listed by the Organic Materials Review Institute (OMRI) and can safely be used on fruit and vegetable crops, ornamental plants and lawns.

Have a growroom infestation? Here's how to quickly win the battle:

Apply Monterey Garden Insect Spray as a foliar spray.
Next, place Mosquito Dunks (in a nylon stocking) in the hydroponics reservoir, or create a soak and use to water soil potted plants.
Lastly, use Blue Sticky Traps to capture any flying adult insects - thrips or gnats that get caught, can't lay eggs! Traps can also be used as an infestation indicator.