On 9 Nov 05 at 11:58, Linda Foulis wrote: > ...I garden indoors a lot. I started off using a mix of > 1-1-1, peat-vermiculite-perlite. Over the years I've > reduced it to half and half of peat and vermiculite. > Needless to say, I'm still looking for the ideal mix... > I have gnat problems every year and I'm convinced that they > comes in with the peat. I'm pretty sure I'm repeating myself, but evidently we have at least one newcomer who might benefit, so please, everyone, be tolerant of reading this all again. Twenty-five or more years ago, I heard a talk by a local herb grower, Capt. Bob Chicken, on his methods. Among the topics he discussed was the choice of soil mix. He objected to soilless mixes (variously mixed from peat, perlite, and vermiculite) because they lacked any clay fraction and therefore had little or no adsorptive capacity for nutrients. [N.B: *ad*sorptive, not *ab*sorptive] He opined that the intended use of these soilless formulas was in sunny California where dilute liquid feedings could be applied regularly. Here in the cloudy Pacific Northwest, if you fed these mixes adequately, you ended up with a soaking wet soil all the time, uncongenial to many plants. His solution was to switch to a soil-based mix, the classic John Innes formula. Because almost all soils have a significant clay fraction, soil-based mixes adsorb nutrients easily releasing them to the plants slowly. Fungus gnats seem to be related to the use of very peaty mixes and mixes with high organic content, and a JI-type formula in my experience doesn't support them as well. These days, I use a simplified soil mix formula combining soil bought in bags from Canadian Tire, perlite, fertilizer, trace elements, and lime. The soil comes from an old lake bed, contains a surprising amount of twiggage and such (you must screen it), and includes both organic materials and silt, the latter providing that all-important clay fraction, the former the moisture retentiveness we associate with peat. But note: no added peat. Moral: consider switching to a soil-based mix. You may find your fungus gnats dwindling away once they're deprived of the gooey, peaty soils they seem to love. It's unlikely that CT carries the exact same soil (Island's Finest "Topsoil") in your area, but they or a local garden center probably have something similar. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island