In your vegetable garden, mulching with straw gives you a long list of benefits. First of all, straw is inexpensive, easy to work with, and good for your soil. And a layer of straw mulch between your rows of vegetables will make your plants stand out and keep your garden looking neat and tidy. Although mulching with straw is a bit tedious at first, it saves you time when weeding and watering in the long run. Unless you garden on a large scale, a bale or two is usually enough to mulch your entire vegetable patch. Here’s what you need to know about using straw mulch around your edible plants.
What is straw?
Straw are the dried stalks left after wheat or oats (or other grains) are harvested. Once the grain is removed, the dried stalks are bundled into bales. Ideally, there are very few seeds or weeds in the straw bale. (Pine straws are simply pressed pine needles and are a good option for mulching ornamental beds.)
Advantages of mulching with straw
Straw mulch not only suppresses weed growth, but also moderates fluctuations in soil temperature and moisture. “A good covering of straw mulch keeps plants cooler and minimizes stress during the hotter parts of the day,” says North Carolina horticultural representative Gene Fox. And because the straw reduces evaporation from the soil surface, you don’t need to water as often. Keeping the soil more evenly moist has many benefits. “Regulating humidity throughout the day is key to preventing physiological problems like fruit cracking and even blossom end rot in tomatoes,” says Fox.
A good layer of straw mulch helps prevent diseases that are commonly spread through spray. “When the raindrops hit the bare ground, particles are thrown into the air and often end up on the underside of the leaves, spreading bacterial and fungal diseases. organic mulch [such as straw] will disperse the velocity of raindrops and minimize soil splashing, which pretty much prevents disease transmission in garden plants,” says Fox.
Developing melons, squashes, and gourds stay cleaner when rested on a bed of straw mulch. It’s also great for strawberries. “Some of my best strawberry beds are with a straw mulch between the rows,” says Beth Chisholm, Whatcom County Community Garden Coordinator at Washington State University Extension Service. “Just keep an eye out for snails,” she adds.
Tips for using straw mulch in your vegetable garden
While straw is an excellent mulch for your vegetable garden, there are a few things you should know to get the most out of this type of mulch. Use these tips when mulching with straw to keep your vegetable plants thriving.
- Use clean straw – not hay! Although they may look similar, straw and hay differ in one important characteristic: hay grown for animal feed contains seeds. When used as a mulch, these seeds will germinate and cause a weed problem. A good quality straw will contain few seeds. When you buy straw, inspect the bale for weeds – weedy straw also sows weeds in the garden – exactly what you don’t want. It pays to shop around to find a reliable source of quality straw; a local farmer, nursery or garden center can usually help you.
- Apply a nitrogen source to the soil before planting. When straw breaks down, it can temporarily rob the soil of nitrogen. This is easily avoided by adding compost, well-rotted manure, worm droppings, or a balanced organic fertilizer to the soil before planting and mulching.
- Don’t put the mulch on until your veggies have been growing for a few weeks. Applying mulch to newly planted seeds can prevent them from germinating. Chisolm suggests an exception to this rule: “When sowing peas or beans, straw is a great way to protect the crop from birds robbing those newly planted seeds.” But just use a light layer of straw until the peas or beans have sprouted and are growing.
- Weed your garden before applying your mulch. While mulch prevents most new weed seeds from germinating, it’s important to remove existing weeds before spreading your straw. “Most annual weeds need sunlight to trigger germination. By preventing sunlight from reaching the soil surface, we can eliminate almost all of our annual weeds that plague our garden,” says Fox.
- Apply the straw at least four to eight inches deep. While this sounds like a lot, the straw compacts quickly, and to get the maximum benefit from the mulch you need good coverage. This insulating layer encourages beneficial microbes that help build soil. It also helps prevent erosion.
- Do not mulch up to the plant stem. Cover the space between rows thoroughly, but not up to the plant stems, which can encourage fungal diseases. A good rule of thumb is to leave one to three inches of space around the plant stems to allow for good air circulation and prevent rot.
- Add more straw as needed during the growing season. Since thatch degrades quickly, you should check around mid-growing season and add extra straw as needed to maintain good coverage. A sufficiently thick layer of mulch is particularly important in the summer heat.
- Use the straw to build up your soil. At the end of the growing season, straw mulch will help improve your garden soil. Fox explains: “Because it breaks down so quickly, tillage can convert the straw into the soil to boost microbial activity. The whole process makes the soil healthier and better able to produce and store nutrients that our plants need to grow.”