Certified GKH Gardening Expert
Fall is a great time to do this. The soil is dry enough to work and you can add all sorts of amendments like compost and rotted manure. They will mellow in the soil over the winter and, in the spring, the soil will be perfect for planting and growing - with no additional tilling in the spring needed. You may want to cover the beds if you work them in the fall to prevent weeds growing in them over the winter.