Answer: Fungus gnats can be so annoying! The spray you used was probably only marginally effective because it's difficult to direct the spray on the quick flying pests. Fungus gnats live and breed in potting soil so your best control option is to place a barrier between them and their homes. I use a two-pronged control strategy. First, water all your plants well and then place plastic wrap over the top of the soil to act as a barrier. You may have to cut a slit in the wrap to accommodate the main stem of your plant (or use several narrow strips to lay over the soil between multiple-stemmed plants). The idea is to exclude the gnats with a covering over the soil. You could use decorative rocks or sand instead if that's more appealing to you. Leave the plastic wrap on the top of the soil for 7-10 days. It will keep the adults from accessing the soil to lay eggs and get water, and it will suffocate any eggs that hatch in that period of time. The second strategy is to place a tall glass with an inch or two of vinegar in it near your plants. The gnats will be attracted to the odor and with any luck they will fall in and drown. Persistence pays off and within a week or two you should be able to eliminate the pests. If you find more, just repeat the process. Eventually you will be able to control the pesky gnats.
Best wishes with your indoor garden!
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