Dear Cathy: Because you are in the mountains, your clay pH could be anything. If it is acid to neutral pH, the gypsum should give you good results. Check with you local county agent for recommended application rates for your area. In clay soils that are already alkaline in reaction (test with a pH kit), gypsum may not be as effective in increasing porosity. I've experienced good results rototilling a product called Turface (calcined clay)into heavy alkaline soils. It is the basis for many of the kitty litter products on the market, minus the price tag. If so inclined, you can repeat rototilled additions of Turface every 2-3 years or mulch heavily throughout the year. As the mulch breaks down it forms a soluble substance (humus) that takes over what the Turface started (creating discrete soil particles that permit water and air to move around them). Turface just jump starts the process (and the rototilling provides enough depth initially for root/bulb growth). I make an annual (when my wife allows) application of manure to the beds during dormancy. Amazing what a little natural fertilizer does for the health of the soil. Hope this helps. Boyce Tankersley btankers@chicagobotanic.org In certain parts of our lot in San Clemente, most notably those areas closest to the house and garage, most everything below about 6 inches is pure clay. Not clay-ey, but pure grey clay (no soil). In the front yard the people who put in the sod applied some gypsum, which did seem to help. I am now working on the beds and they need a lot more work than was done to sod the lawn. Anyone interested enough in this issue to discuss this topic? In particular the gypsum issue? Thanks! Cathy Craig President PBS Maritime zone 9b _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://www.pacificbulbsociety.org/list.php