I have developed a moderate problem with fungus gnats in some of my house plants this winter. The worst affected are some small pine trees (less than 6" tall) that I transplanted and am overwintering indoors. Will they harm the plants? If so, any safe and organic suggestions on how to get rid of them?
A few methods appropriate for indoor use are beneficial Nematodes, BT and yellow sticky traps. The gnats love the organic matter in your soil and usually wont cause too much damage unless the population is high. An inch or so of pure sharp builders sand on top of the potting soil surface will help to discourage them but you must also prevent access to any bottom drainage holes.
