Cathy Craig asked, > >In much of Southern California we have clay soil. 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. > >I bought a bag of gypsum today. Customarily I just dig out all the old soil >and have it hauled away. I am going to try amending some of it but there >aren't very many instructions on the gypsum bag and no explanation at all on >how it works or why it works or whether it 'wears out' over time and I will >have to re-do the whole job again in future. Here is a quote from the forthcoming "Rock Garden Design and Construction," the chapter on soils by Louise Parsons. If Louise is a member of this forum, thanks are due to her for this excellent chapter, which you will be able to read in toto next fall when Timber Press issues the book: "For example, some clays have very specific properties of adhesion, particularly to the common yet highly variable mineral feldspar. If you have a clay-feldspar incompatibility, mixing in grit or sand that contains large quantities of feldspar will produce a nasty concretelike soil. Some soils are gypsum-receptive, while others are not: adding gypsum, often recommended by general gardening manuals, does not automatically balance or even influence pH in all soil types. Still other soils contain a clay that adheres to gypsum, producing a concrete or crusty hardpan. You can spend a lot of money on this popular additive, only to make textural problems worse." Apparently Cathy's soil is "gypsum-receptive." There is a great deal of information on making rock garden soils in this forthcoming book, and I'm sure it will help bulb growers as well. Jane McGary NW Oregon