It sounds like you have a problem with fungus gnats. Fungus gnats are small, grey flies about 1/4 of an inch long. They are found in moist, peat based potting soils that are rich in organic matter. Damage is done by the larvae and can be fatal to young seedlings. There is usually no noticable damage to mature plants. Adults may transmit crown or root rot.The adult females will deposit between 100-150 eggs on the soil surface near the plant's stem. The eggs hatch in 4-6 days into white larve with black heads. They feed on decaying organic matter and plant tissue. They pupate into adults 3-4 days later.
To control, reduce the amount of watering. Allow the top layer of potting soil to dry out. Most larvae are seen in the top one inch of soil. If you cover the slil with a layer of sand, the adult may not lay her eggs in it.
Yellow sticky tapes can be used to trap the flying adults.
You can drench the soil with Bacillus thuringiensis (Bt. Chemical controls can not be used with Bt.
You can try some diazinon or pyrethrin on the affected soil. This would have to be done every few days to attack all stages of the insects development (just think of all those eggs!).
Good luck
Barb barbsblooms@shaw.ca
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I've purchased a spray for the problem and it didn't do anything. Do you have any suggestions on what to use or home remedies I can try? I'd really appreciate the help. My poor plants. 
Printer-friendly view of this garden