Expert advice Winter digging
This is a seasonal must-do job. Although it is laborious (it is also called double digging), it is the very best way to improve soil quality, especially in a new plot or one that has been neglected for a long time. The best time to do it is during a dry mild spell; avoid digging when the soil is very wet or frozen.
Double digging not only breaks up compacted soil and helps drainage, but by incorporating lots of organic matter such as compost or well-rotted manure while you’re digging, the soil’s fertility will be improved. You will see the difference in the quality and quantity of plants in the following season, whether it’s in a flower border or a vegetable plot.
Adding ridges at this time, especially if the soil is heavy, creates a larger surface area upon which cold weather will work to break it down and improve its quality.