Is It Okay to Mulch Summer Squash With Old Straw?

Straw vs. Hay

• If you haven't spent a lot of time on a farm, you may think straw and hay are interchangeable -- they're not. Straw is the stalks of harvested grain plants, usually dried to a bright gold and bundled into bales. Hay is cut grasses and legume plants used as animal feed. It purposefully includes seed heads to provide added nutrients to animals. Hay is greener and heavier than straw with finer stalks. Mulch with hay, and the finer material tends to mat, filling your garden with sprouting seeds. Straw is light and fluffy, and is generally less expensive than hay. It is readily available at both farm supply and garden centers.

Preparing Straw Mulch

• Unlike hay, while seeds aren't intentionally included in straw, there are usually a few stragglers to be found -- one reason you should purchase your hay in the fall to use as spring mulch. Any stray seeds will sprout as you leave it outdoors over the fall and winter, so it's ready to mulch your summer squash in late spring. Leave purchased straw in bales outside to get wet and begin to rot -- any seeds will sprout, and with the decomposition process underway, the hay ties up less nitrogen in the soil necessary for the growth of your squash. Straw used as animal bedding, particularly in chicken coops, is a mulch that also includes a source of nitrogen. Use it only after composting it for a season; otherwise, the nitrogen is so "hot" it can burn your plants.

Installing Straw Mulch

• Once your garden soil warms to 60 degrees Fahrenheit in late spring, and you have either seeded your summer squash in place or planted out seedlings, it's time to lay down straw mulch. The bales pull easily apart with gloved hands. Apply straw by the handful in fluffy, 3- to 6-inch layers. Keep the straw back from the base of the developing squash plant to prevent rot on the stem.

Benefits of Straw Mulch

• The partially rotted straw mulch not only does its basic work of weed suppression and moisture conservation, but has numerous other benefits over other mulch options. Because it's lightweight and doesn't tend to mat down against the soil, it allows for air circulation that encourages healthier roots. According to the Austin (Texas) Organic Gardeners, straw also attracts spiders, which feed on many garden pests, and repels aphids, a particular pest of summer squash. One of its biggest benefits is that when it's time for new mulch, you can simply till it into your garden to add organic material or rake it into the compost heap with other organic material to finish decomposition into nutrient-rich compost.