We am surrounded by clay soil here in San Jose and it's not the pottery clay soil you might think. It's full of minerals and micronutrients but come mid-summer, you can't dig it at all. It's quite workable after the first few rains in fall and for a period after the rain stops in late spring. Excellent drainage is defined by how long water takes to drain out of a certain sized hole. It can be an hour or it can be 12 hours, depending on the type of clay. Here's a very good treatment of soil that you'll enjoy reading: Teaming with Microbes: A Gardener's Guide to the Soil Food Web by Jeff Lowelfels He's a very popular speaker here on the West Coast and if you get a chance to hear him, do go. Cheers, Bracey San Jose CA -----Original Message----- From: pbs-bounces@lists.ibiblio.org [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of Laura & Dave Sent: Saturday, May 15, 2010 12:56 PM To: Pacific Bulb Society Subject: [pbs] A soil question Hello all Perhaps some of you can explain something regarding soils to me. I was looking up culture for potted "Ipheion sellowianum" (yes, I know that it may be called something else now), and I have once again run across the phrase "a clay soil, rich in organic matter". When I think of clay, it is the type found for making into pots, bowls, plates and chalices. There is no organic matter, that I know of. When I've dug around in the ground in Southern Ohio, at my in-laws' place, there seems to be a layer of organic matter on the surface, in various stages of decay as one descends into the soil, and then a fairly homogeneous layer of clay, reaching down to bedrock. Is the organic matter spoken of in the clay in a micro particle state in the clay? Or is the organic matter at the molecular scale; that is, only organic molecules? Does one duplicate this soil by putting compost into clay, and knifing it in, kinda like making biscuits with shortening and flour? What substitute soil type fools the plants into thinking that they are in their ideal conditions? I've come to the conclusion that soil is the key to understanding plant growth; if you reverse the way one looks at plants, with the main organism underground, and an attached solar collector, ventilation system and reproductive organs all stuck up to wave around in the weather, you see what I'm thinking. However, the study of soil is a difficult subject, and I'd welcome any help here that I can get!! Thanks Dave Brastow, Tumwater Washington (7A)