This is the perfect time of the season to take care of mulching your vegetable garden. Often gardeners take time to mulch their perennial, shrub, and other beds, but they don’t think about mulch in their veggie beds. Given that your vegetable beds likely use the most water of any areas in your garden, mulching can go a long way in helping conserve water, keeping weeds under control, and in keeping your veggies happy with more consistent moisture. Here is a quick primer on different mulch materials you might consider:
This type of mulch is used very early in the season (typically being put down in April) to warm up the soil for plants that will be planted later, such as tomatoes, peppers, and squash. If you are going to use plastic to warm the soil, be sure to use a thick plastic (5 mil or so). Don’t use plastic garbage bags since they aren’t thick enough, will tear easily, and will soon be blowing around in your garden in the spring winds. Instead, check in the painting supplies section of your hardware store for drop-cloth quality black plastic. Usually holes are then cut in the plastic in mid-to-late May to accommodate transplants. If the plants haven’t grown large enough to shade the plastic once temperatures are routinely in the 80’s and 90’s, remove the plastic mulch and replace it with one of the following organic mulches.
Dried, herbicide-free grass clippings (this means an herbicide has *never* been applied to it) can make a good mulch for the vegetable bed. Lay it in a layer at least 4-to-6 inches thick. If you only have fresh green cut grass, either apply it in very thin layers (allowing to dry out and yellow before applying more), or put your fresh clippings in an out of the way place to dry out and age a bit before using them. The clippings can be dug into the soil in your fall clean-up.
If you can find a source of good, weed-free straw (weed-free is key!), this is a good mulch option for the vegetable bed. Layer it about 4-to-6 inches thick.
Leaves that have been shredded or partially composted in a leaf pile make a better mulch than dried whole leaves since the whole leaves are likely to blow away with the first good wind that blows through. But shredded or partially decomposed leaves will compact a bit more and stick to the ground, especially if you water after applying it in a 4-to-6 inch layer.
Largish wood chip mulch is also a viable vegetable bed mulch. This type of mulch is often available at free mulch pick-up sites. Don’t use a layer thicker than about 3 inches. This is reusable. Rake it off or to the side before doing your fall clean up and soil amendment, and then rake it right back over the bed to wait for next year’s planting.
Three-to-six layers of newspaper can be an effective, if unattractive mulch (unfortunately it’s not recommended you used the colorful Sunday comics!). Many gardeners like to use newspaper topped by another organic mulch to suppress weeds.
You can read about many more types of mulch and their applications in CSU fact sheet 7.214, Mulches for Home Grounds.
Submitted by Carey Harrington, Colorado Master Gardener. (Photos by Colorado State University Extension.)