diatomaceous earth -- works when dry, not wet...
Get food-grade.. DO NOT get filter-grade or filter quality.. that's no good indoors around living things.
food grade will not give "pesticide instructions" but it works exactly the same way... bugs walk across it, f%#$ks with their exoskeleton and the dyhydrate or eviscerate themselve son it, i forget.. but it sounds wonderfully painful for them in either case... so, bonus.
it's a great way to go instead of spraying neem oil or some other pestides.
line it aorund growbox/tent... put it on ground in your tent.. etc.. whatever workse best... it can be messy, so inside is better... and don't appy it when plants are in there... expecially bloomign plants.. .you'll just get DE on your buds,lol.. fans can't blow on it, etc.. it'll go all over the place.. so it needs to be used in correct contexts.