Mulch is a valuable addition to the vegetable garden growing environment. An organic mulch blocks most weeds and helps even out soil temperature and moisture content changes, protecting fragile plant roots from stress. Organic mulches also improve soil tilth, friability, and nutrient content. Wood chips are one type of inexpensive organic mulch you might consider for your vegetable garden.
In considering wood chips, start by evaluating the advantages. Wood chips are often free or inexpensive from a municipal composting facility, utility-line tree-service contractors, or local landscapers. The low cost represents a significant advantage over most other organic mulches like pine bark, cedar bark, or cocoa hulls, which can be quite expensive.
Because wood chips are cheap, it is convenient to layer them on the garden soil quite thickly, which does an excellent job of discouraging weed growth and also provides some warmth to the surrounding plants through thermogenic decomposition on cool autumn evenings.
Wood chips have a high carbon-to-nitrogen ratio, which means that as they decompose they draw some nitrogen from their immediate environment. However, the amount drawn is small if the chips are used on the surface of the ground as a mulch rather than turned into the soil, and the net nitrogen draw ceases once the chips have decomposed. To ensure maximum nitrogen availability for your vegetable garden crops, spread a thin layer of well-aged compost, or a light application of nitrogen-rich fertiliser, on the surface of the ground before layering in your wood chip mulch.
Ageing the wood chips for one year before using them for mulch will also decrease the nitrogen draw, and result in a drier, lighter, more grey-toned stock of wood chips to work with. Also use the wood chips as a bulking agent and carbon component of your home composting, and then use the fully-aged compost as mulch as well as in planting as a soil additive.
Some trees, particularly black walnut and butternut, contain a chemical substance that deters plant growth. Determine the source of the wood chips you intend to use as garden mulch, and avoid mulches with any walnut-family wood content.
Other aromatic wood chips, such as cedar or pine, can irritate some people's skin, and although many people like the smell of these woods, others find it bothersome. Sniff the wood chips you intend to obtain or use in your vegetable garden, and avoid strongly aromatic wood chips if you have skin or breathing sensitivities.
Wearing closed-toe shoes, long trousers, a long-sleeve shirt and gardening gloves is always a good idea when working in the garden, to help avoid spider bites and other garden hazards. When digging in or kneeling on wood chips, this also helps for avoiding splinters.