lime

Have you tested your soil type first?  Lime is usually only needed for brassicas, but it does depend on your soil type.

You will probably need to add some manure, blood fish and bone or similar nitrogen based feed such as pelleted chicken manure.

If you want to grow brassicas, it is worth investing a small amount of £ on a chemical soil tester - not difficult to do either, I tested the soil on my new plot last year, so look at the link on my signature if you want to find out more.