Mulching is a useful technique in the vegetable garden to save on weeding and help conserve moisture. There are various products around, so which is best?
Straw: can be effective, especially for conserving moisture but in a wet summer it will harbour slugs. It does keep your boots nice and clean, though.
Grass clippings: free and effective. Just cut grass can get too hot for growing plants as it breaks down, so lay it out in the sun to dry, cool it down and spread it around. Especially good round potatoes, squashes, pumpkins and courgettes. As it rots it will add valuable nitrogen to the soil.
Strulch: a mineralised straw product. Not cheap but it suppresses weeds incredibly effectively and has a poor capacity to hold water so rain runs straight through to the soil. This means the surface stays dry, which helps keep the slugs away.
Bark: not a good choice for the veg patch as unless its properly rotted down it can cause nitrogen lock-up and it harbours slugs.
Alys Fowler in The Guardian Weekend, 2011
