Soil amendments are mixed into the top soil to improve the soils drainage, nutrient levels and available oxygen. Large wood chips decompose slowly and are best used to improve drainage and aeration in soils with high clay content. However, although wood chips do improve the soil, they also temporarily tie up some of its available nitrogen. Contact your local county extension office and arrange to have a soil test conducted one year after you amend the soil. The results will tell you if you need to add more nitrogen to your plant's fertilizer.
Loosen the top 6 to 8 inches of your soil with a hand tiller. Remove any rocks or other plant debris that you encounter along the way.
Spread a 3 inch layer of large wood chips. Follow it by a 1 inch layer of manure or compost to replace the nitrogen that the wood chips will leach out of the soil.
Turn the soil again, thoroughly mixing the amendments into the top 6 inches of the soil.