Sheet Mulching or building Lasagna Mulch
Another method of mulching that works well for discouraging weeds is what is sometimes called sheet mulching. You will be building a mulch by layers building what is in effect a horizontal compost heap by layering nitrogen and potassium rich ingredients. This is a good use of leftover grass clippings.
1) Begin with a 2 inch layer of compost. This can be laid on bare earth but even on top of grass or weeds that have been mown as short as possible.
2) Add 2 inches of grass clipping and water well.
3) Add either a layer of cardboard or newspaper. If you use newspaper in needs to be at least 8 layers thick. Sprinkle with water to hold it in place.
4) Cover with 3 inches of compost.
5) Finally, add a layer of organic matter such as wood chips, shredded bark or sawdust.
6) Larger plants and seedling can be nestled into the mulch. The roots will grow down through the layers of mulch and into the compost below. The compost and clippings underneath the paper will break down the grass and begin improving the soil, turning the entire bed into a well-drained, moisture-retaining plot for vegetables or flowers.