Our village has a compost area. For soil, I use the composted leaf / yard waste and add composted horse manure from my own horses. Just having a huge raised bed project to do in a hurry, I bought topsoil (a truckload) This soil is pretty lacking in organic matter but I will mix in manure. I also fertilize with bone meal, rock phosphate and lately I've added some kelp meal to the new beds just because I happen to have a bunch left over from a homemade horse supplement. I also add wood ash from the stove to raise the ph (acid soil here and manure is acidic too) and provide potash.
I too am amazed at the pictures of the famous iris farms' soil. My gardening background is as an organic veg gardener. This flower thing relatively new, a luxury enabled by moving from Los Angeles to rural New York state where there is water. I'm used to thinking of a good soil as something dark, rich and crumbly, but dang if these miraculous irises won't grow anywhere.
My garden soil helpers
