A good, thick layer of mulch can smother weeds, improve the fertility of the soil, increase your yields and reduce the amount of watering you need to do, all at the same time. You can bury drip irrigation line underneath the mulch to make watering easier (though more difficult to spot leaks). Mulch in layers, with nutrient rich materials (lawn clippings, garden weeds, animal manure, rock powders, etc.) near the bottom and rougher materials (such as cardboard, rice straw and wood chips) near the top. You can lay one year’s mulch right on top of the previous year’s.
Be sure to use weed free mulch material, such as cardboard, lawn clippings, wood chips and rice straw. Hay and straw other than rice straw may contain noxious weeds that will cost you more labor than the mulch saves you!