I'll second the pest strip idea, especially if you're able to keep them relatively close to the soil. Fungus gnats (and their larvae) spend a lot of time in or around the soil, so you're only going to have limited results from foliar spraying. You might have better luck spraying the surface of the soil with the soapy water rather than just the leaves. Also, be sure that there's no standing water in the collection trays under the pots. Moist, stagnant areas like that are perfect breeding grounds for the little devils.

Take care. :jointsmile: