My hobby is growing house plants. I used to have a business selling tropical and garden starts. 2 months ago I was at a friend's house and soil gnats were flying up my nose. Everyone was waving their hands in the air the whole time we were there. I told her about a method to get rid of them, and when I went back recently I noticed her house was free of those bothersome gnats! Here is my method to get rid of them: When it's time to water your plants, use hot water. Turn on the tap and get it just at the point where it's as hot as possible but you can still stick your hand into it. Water all plants in the house at the same time with the hot water. If the water in the container cools as you are walking around watering the plants, replace it with fresh hot water so that each plant gets the hottest water possible. Repeat every 7 days for a month. Repeat in future if soil gnats appear again. The hot water will not hurt your plants any more than it hurts your hand. It will not hurt the leaves or roots at all... in fact, hot water has some things in it that are beneficial to the plant, although you don't want to use it all the time. This is a good method to get rid of scale, mites and aphids w/o using chemicals: Fill a spray bottle with 30-35 drops Grapefruit Seed Extract and bottled water. Spray the entire plant - top and underside of every leaf, stem and woody cane, and spray the top of the soil. Repeat every 7 days for a month. For large, resistant scale patches, wipe with a baby wipe after spraying, then spray again (always wash hands after touching any plant with these diseases). A water+alcohol or water+vinegar spray will also do the trick.