Mulch mulch and more mulch is a must for getting humus into clay soil.
Does your soil sticks to your shoes and garden tools like glue? Is your soil slow to warm up in the spring and hard to manage? If your soil is slow draining, forms big clods, crusts over and cracks in dry weather then you have clay or even heavy clay soil. Clay soil is made up from very fine particles that make pure clay good for potters but not plant roots. One redeeming feature is that clay soil is generally rich in nutrients.
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