Ask Alys: your gardening questions answered

I've just moved into a house with a 29 sq m garden that was entirely concreted over. I've taken it all up, and there's no sign of worms in the soil. How do I improve it? You need compost – and lots of it. The most economical way is to make your own. In a small space, a wormery or bokashi bin are the best way to do this. They're self-contained systems, so won't smell and will quickly produce rich organic matter that's perfect for reviving tired soil. Many councils now offer subsidised bins. Also, find out how to get hold of green waste compost, which is produced by all councils these days: some sell it to the public, others offer it free. It is often rough stuff, but it is ideal for energising tired soil. In autumn, collect brown leaves and rot them down in bin bags or a wire cage. This will take up space, but the more you put in, the more your garden will reward you. Whatever compost you get, add as much as you can. Once it's there, the worms will find their way to your garden soon enough. I wouldn't bother digging it in, though, because they'll incorporate it into the soil far better than you ever could. • Got a gardening question for Alys? Email [email protected]