Try diatomacious earth. Basically it is a fossil that has a high liquid absorbtion capability and when the insect walks on it, it absorbs the water from their exoskeleton and causes them to die. Chemical composition is silica sodium magnesium and iron so likely will not overfert by adding it to the soil surface. Just be careful applying it maybe wear something over ur mouth (bandana, painter's mask) because it can be harmful to inhale or ingest certain types.

Edit: Hmm I guess they lay their eggs in the webbing so I don't know how well this would work but very good preventative method. However if they walk on soil sometimes this would be good.
bloodbrother Reviewed by bloodbrother on . Spider mites getting aggressive at 5th week flowering Hi there, What to do if you find a lot of spider mites and their eggs around 5th week of flowering? I have the impression that it is now way too late to stop them from spreading everywhere, but fortunately most of the upper buds are still intact. Should It be harvested right away? I know it's not entirely ready but there are quite a few trichomes already. Nothing amber tho, mostly clear/white. (see pic) I'm just thinking perhaps it would be better to harvest what is possible to save right Rating: 5