In a message dated 1/23/2010 10:13:01 PM Eastern Standard Time, aaron_floden@yahoo.com writes: Gypsum never did a thing for the clay I had in Kansas, even when added in large quantities (50lbs/10 sq ft). The only thing that helped was collecting 100+ bags of leaves each fall in addition to what fell naturally in the yard and adding them as mulch after being chopped. After three years of this the soil improved immensely. Whatever you do, be very cautious about mushroom compost obtained from outside sources. I used that on a new bed one year and lost everything I planted in it, both perennials and bulbs. A pro at a big public garden here told me later that they use it, but that they compost it another year further themselves and then have it tested before applying because they can't afford to lose a bed. I am surrounded by woods, and also have many of my own trees. I don't waste a leaf in the fall--it all goes through the shredder and into one of the 5-block-high compost piles for addition to the beds during the year. You can't beat that stuff! Bill Lee SW Ohio