I have very heavy clay soil, so I tilled it into my raised garden (3 yards) 20'x 15' and then added 1.5 yards more of the compost and worked it in very well with a shovel. The compost is cottonburr and my question is, is this too much compost and/or should I add a bunch of plain topsoil to fix it or not? Thanks.
Cotton Burr is compost made from the byproducts of the cotton ginning process.
The byproduct is sold as regular or acidified versions.
The acidified version has sulphur added to lower the ph of the soil.
The nutrient level is approx. 1-0-1, which means that it is 10 percent nitrogen, 0 phosphorous and 10 percent potassium.
Cotton Burr should be used along with other forms of soil additions and fertilizer.
Add 2 to 3 inches of Cotton Burr to the garden beds and rake or till in to the soil at least 8 to 10" deep.
After you have worked your clay soil with the addition of the compost you should check your soil.
How does the soil feel? Heavy and still clay filled, or loamy and light?
A soil test is a great way to help determine what you can add to your soil for gardening success.
Here is a link to help you locate the closest Extension Office that can help you with a soil test.