Mulches are often recommended for vegetable gardens, but choosing the right one can be daunting. The best mulches conserve moisture and minimize weeds. Organic mulches, according to the Virginia Cooperative Extension Office, have the added benefit of improving the soil. Cedar mulches are among the most expensive, but are very durable.
Mulches are used in vegetable gardens for several reasons: to warm up soil, to minimize weeds, to conserve moisture and to improve soils. Cedar mulch can be spread as a 1- or 2-inch layer over garden soil directly around vegetables. It is more often used, though, as mulch for paths between raised beds.
Cedar mulch is the most expensive wood mulch, and with good reason. It decomposes slowly, smells good and may even have some insect repellent qualities due to the oil it releases. Cedar mulch is attractive and heavy enough that only very heavy winds will move it.
Decomposing wood chips initially have a high carbon-to-nitrogen ratio, meaning that they take nitrogen from the soil, making it unavailable to plants. Most vegetables require a lot of nitrogen to grow, so applying fresh cedar mulch to young plants might slow growth. Cedar mulch doesn't decompose quickly enough to be considered a good soil amendment and it must be raked and removed every fall from vegetable beds in anticipation of spring planting. Additionally, cedar mulch planted too closely to young plants might suffocate them.
Cedar mulch is a good choice for garden paths between raised beds. Especially when combined with landscape fabric, it provides an effective weed barrier. Cedar mulch is attractive, long lasting and may repel insects.
Black plastic, untreated grass clippings and weed-free straw are better options for mulching vegetables. Black plastic, while unattractive, warms up the soil, limits weed growth and works especially well with heat-loving crops, such as melons, peppers and tomatoes, according to Barbara Damrosch, landscape designer and author of "The Garden Primer." Untreated grass clippings and straw smother weeds, conserve moisture and break down into the soil. They don't need to be removed, but can be tilled under during fall cleanup.