IMO the easiest and most effective way to kill and prevent fungus gnats from breeding in your soil is to simply sprinkle a little bit of Diatomacous Earth on top of your soil.
It causes the little bastards to "bleed out" upon contact .
What is Diatomaceous Earth?
Diatomaceous earth is a remarkable, all-natural product made from tiny fossilized water plants. Diatomaceous Earth is anaturally occurring siliceous sedimentary mineral compound from microscopic skeletal remains of unicellular algae-like plants called diatoms. These plants have been part of the earth's ecology since prehistoric times. It is believed that 30 million years ago the diatoms built up into deep, chalky deposits of diatomite. The diatoms are mined and ground up to render a powder that looks and feels like talcum powder to us. It is a mineral based pesticide. DE is approximately 3% magnesium, 33% silicon, 19% calcium, 5% sodium, 2% iron and many other trace minerals such as titanium, boron, manganese, copper and zirconium. Diatomaceous Earth is a natural (not calcined or flux calcined) compound. Diatomaceous Earth is a natural grade diatomite. However, the continual breathing of any dust should he absolutely avoided.
How does it work?
To insects DE is a lethal dust with microscopic razor sharp edges. These sharp edges cut through the insect's protective covering drying it out and killing them when they are either dusted with DE or if it applied as a wettable powder spray. If they ingest the DE it will shred their insides.
http://www.ghorganics.com/DiatomaceousEarth.html
http://www.dirtworks.net/Diatomaceous-Earth.html
http://www.earthworkshealth.com/
http://www.planetnatural.com/site/di...ous-earth.html
Just ordered some from ebay,cheers for the advice guysthink ill invest in this the nxt time.