7 of the Best Mulches for Vegetable Gardens (Why Mulching is Essential)
How to use mulches to improve soil and retain water
Wood chips might be top of mind when it comes to mulching, but you can technically mulch your garden with any material that will cover the ground. Other than wood chips, the most common mulches include landscape fabric, straw, grass clippings, leaves, cardboard, and even compost.
Mulching has many benefits: primarily, it helps the soil retain moisture so that heat and drought don’t damage plants as much. But mulch is just as useful in the winter since it insulates plant roots against the cold. Proper mulching can also cut back on some foliar plant diseases caused by water droplet backsplash as a result of watering.
In this blog post, we’ll discuss the best types of mulch to use in your vegetable garden, as well as how (and when) to apply mulch for the best results.
Benefits of mulching
Mulching does so much more than add an attractive aesthetic to your garden—it’s functional too. Adding mulch to your garden:
- Conserves water;
- Insulates plant roots during winter;
- Suppresses weed growth;
- Slows the spread of disease due to backsplash;
- Slows erosion;
- Attracts beneficial insects;
- And adds visual appeal!
Now that you know why mulching is important, let’s talk about what you should mulch with.
7 awesome mulches for the vegetable garden
There are a lot of different mulches on the market, but it really all comes down to two broad categories—organic and inorganic.
Organic in this sense doesn’t mean what it typically means here—an organic mulch is any material that was at one time alive (straw, wood chips, leaves, compost) whereas an inorganic mulch is any man made or non-living material (landscape fabric, gravel, rubber). Organic mulches break down and enrich the soil over time, but inorganic mulches do not decompose.
Take your pick of any of the following mulches: or try a combination of a few different types of materials! Of course, you can use any of the mulches in the flower patch or perennial garden, too.
Compost actually makes a great natural mulch for your garden, plus it improves the soil tremendously. Rich in nitrogen and other organic matter, compost adds nutrients to the soil, as well as introduces beneficial microorganisms like worms. The varying sizes of compost particles and microorganism activity improve the texture of the soil, allowing it to both retain and drain water better.
The only drawback of using compost as mulch is that it is quick to decompose, so it isn’t a good long-term option since frequent reapplications are necessary. To effectively suppress weeds, the compost should be spread in a layer at least two inches thick—in a big garden, that’s a lot of compost.
Unless you’re making compost at home, buying compost can be expensive, so it’s not always the cheapest option—but it’s worth the price.
Wood chips are the most common mulching option, but not all wood chips are equal. Bagged wood chips are okay in a pinch (as long as they’re not dyed or made from treated pallets), but nothing compares to fresh wood chips from a trusted source.
Wood chips that have aged for six to twelve months are ideal for mulching since unaged wood chips can temporarily tie up nitrogen in the soil.
Although wood chips are fine to use on the soil surface, avoid tilling wood chips into the soil at the end of the season. Layer wood chips at least two inches thick for an effective barrier against weeds.
One of the cheapest mulching options is also one of the most effective at retaining heat in winter.
There’s one caveat with using straw as mulch—make certain that you’re buying straw and not hay. Although many of us use the terms interchangeably, hay technically describes entire dried plants (seedheads and all) whereas straw describes dried plant stalks only. Hay is used for animal feed, and straw is better for animal bedding and mulching since the chance of introducing weed seeds into your garden is much less.
Straw, similar to wood chips, affects nitrogen levels in the soil. Though neither material truly depletes the soil of nitrogen, this essential nutrient becomes unavailable to plants as straw and wood chips decompose. Applying a layer of compost underneath either mulching option is a great way to mitigate this issue.
As inexpensive and effective as straw is for mulching, it is lightweight. Apply a layer of straw at least four inches thick (the straw will compress with time) and water it thoroughly to keep it from blowing away.
Leaf mold, or leaf compost, is a long-time favorite mulch of many growers. Like compost, leaf mold is rich in organic matter and nitrogen, so it does double duty in the garden—it serves as a mulch and soil amendment, simultaneously.
If you have deciduous trees in your yard, you can collect and compost your own leaf mulch at home. Simply sweep up fallen leaves in autumn and make a pile somewhere in your yard. Water the pile and monitor it over the next few months, adding water when the pile looks dry. Turn it a few times over the winter, and in spring you will have fresh leaf mold!
There’s one caution with leaf mulch—avoid using leaves from walnut trees, as these leaves contain a chemical that is toxic to most vegetables.
Pile on a layer of leaf mold about two inches thick, or make the layer an inch or two thicker if using whole or only partially decomposed leaves.
Put the grass clippings from mowing your lawn to good use as mulch for your garden! Grass clippings break down fast so they aren’t a good long-term solution, but they are free and are sure to add nutrients back into the soil.
Only use grass clippings from lawns that haven’t been treated with a herbicide—if you’re not sure of the status of the grass clippings in question, it’s best just to pass.
Let the clippings dry out fully before adding them to your garden, layering them a couple of inches thick. Dig any leftover grass clippings back into the soil at the end of the year to enrich the soil for the next growing season.
Landscape fabric & plastic
Even though it’s made of plastic, landscape fabric is one of my favorite mulches because it’s fairly durable and can last for years when used and stored properly.
These large pieces of woven polyester or polypropylene are the best weed barriers around, but their tendency to absorb heat makes this mulch better suited for heat-loving plants. Landscape fabric is the one mulch that you want to lay down before you plant, since it’s nearly impossible to pull a sheet of landscape fabric over tiny seedlings without damaging them.
Landscape fabric is typically secured with steel landscape staples and weighted with rocks or t-posts.
The one drawback of landscape fabric is that it will blow away if not secured correctly. It can also repel water, so installing a drip irrigation system underneath the fabric is essential.
Landscape fabric is extremely customizable and reusable—as long as you mark which fabric goes with which bed. You can also use landscape fabric to mulch permanent paths and beds.
Red Mulch Film is one of our favorite mulches for heat lovers like tomatoes and peppers. The plastic film is multipurpose—use it as a row cover to warm up garden beds before planting, and use it to suppress weeds and increase yields after transplanting.
Cardboard & paper
Although not the most attractive mulch, cardboard is an inexpensive and effective mulching material for vegetable gardens. Cardboard is generally easy to come by (you can save your own or get a local business to donate their recycling to you for free).
While cardboard is excellent at suppressing weeds, dry cardboard can repel water so you’ll need to water cardboard after laying it down on garden beds. Use rocks or cinder blocks to weigh the cardboard down and keep it from blowing away in the wind.
Remove any staples or tape from cardboard before using it as mulch, and avoid using glossy or colorful pieces that might contain toxins.
Other paper products like newspaper or cardstock make decent mulches, but they won’t last as long as cardboard.
Planters Paper Mulch is the best of both worlds, combining the effectiveness of black plastic with the biodegradable component of a paper product. Lay Planter’s Paper Mulch just as you would landscape fabric and weigh it down with rocks or soil. Cleanup is easy: at the end of the season, simply till it back into the soil!
How to apply mulch (the right way)
Mulching is almost as simple as it sounds, but these few tips can make a world of difference.
1. Mulch annually in mid-spring
As a general rule, aim to mulch once a year. Some mulches, like grass clippings or leaves, may need to be applied two or three times throughout the growing season, whereas other mulches like landscape fabric can last for years.
The best time to add mulch is in mid-spring or early summer—just before summer temps begin to soar and weed seedlings take off. If you’re unsure, aim for later rather than sooner, since mulching too early can cause soil temps to warm more slowly than normal.
Avoid mulching in midsummer because the extra material can make plant roots too warm! Re-mulching in the fall is a great way to insulate and over-winter perennial plants.
2. Choose the best mulch for the crop
Heat lovers like tomatoes and peppers love black plastic, but cool-season veggies like broccoli prefer natural mulch with cooling properties, like straw or leaves.
3. Weed and water the bed first
Before you lay any kind of mulch, weed the garden bed and water it thoroughly. Some mulches are better at suppressing weeds than others, and some mulches hold water better than others. Mulch doesn’t necessarily kill existing weeds, but it will slow and even halt weed seed germination.
4. Spread mulch after transplanting
You can plant into a bed covered with mulch, but it’s far better to mulch around established seedlings. A few exceptions to this rule are large seeds that birds often get—like beans, corn, and sunflowers. In these instances, it may be better to lightly cover the seeds with a lightweight mulch (like straw) for protection.
5. Leave some space around plants
While it may be tempting to mulch right up the base of your plants, you’re better off leaving plants some space to breathe. Clear any mulch within a two-inch radius of plant stems and roots to allow good air circulation and deter fungal diseases.
6. Install drip irrigation
Natural mulches like wood chips and straw allow water to pass through, but other mulches like black plastic and landscape fabric aren’t as permeable as natural materials. Either way, it’s a good idea to install drip irrigation underneath plastic mulch and on top of natural mulches.
Not only does drip irrigation conserve water and save your water bill, but you can control exactly how much water your plants get. You won’t have to worry about their roots drying out underneath the mulch, even on the hottest summer days!
Mulching does so much more than add visual appeal to the garden—it really does result in healthier and more productive plants. Mulching helps the soil retain moisture, insulates plant roots against the cold, and reduces water droplet backsplash.
Both organic and inorganic mulches are safe for vegetable gardens, and whichever material you use really comes down to personal preference.