I only use 35% so if you have household 3% it would be aprox 12 ml, about two and a half tsp(I'd go less!) but you only need the minimum to do the job. Remember this "isn't" an effective insecticide!inflorescence said:badmf, I know you've been around (same handle on OG?) and you've always dished out some good info but 1 ml/gal is basically 1/5 tsp/gal. Most people say 1 tsp/gal (3%) is ok and as was posted here people use up to 1 TBS/gal. Are all these people harming the root hairs without knowing it? Maybe, but it just seems like 1 ml/gal is low.
As Richeyrich says j"just use Gnatrol"! Peace
PS Same as OG, lol