Select the right garden mulch
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EmailMulch can help reduce weed competition, increase your garden's productivity, and reduce the time you spend working in your garden.
Challenges in the garden are a regular part of growing plants. One of the most common issues in vegetable gardens and newly established beds is weeds. When weeds get a head start, they can quickly overpower your other plants. One of the most effective ways to drastically reduce weeding time is to use mulch. Covering the ground with mulch reduces the amount of light reaching the soil surface, which prevents or at least slows weed seed germination.
Weed suppression isn't the only benefit. Mulches can be used to moderate soil temperatures, reduce moisture loss from the soil, and even add organic matter in the case of organic mulches. Now that you have discovered the benefits of using mulch, let's explore some common options you may encounter.
Organic mulches
Wood chips
These are an excellent choice for perennial beds and walkways in vegetable gardens. Due to their thickness and slow decay, they are less desirable in annual and vegetable beds, where the layout may change from year to year. Arborist chips can sometimes be acquired for free from local businesses. These free chips often vary in size, and you won't have any control over what type of wood they are.
Straw
Straw is an excellent choice for vegetable beds and protecting newly planted seeds. It can occasionally harbor slugs and snails. There may be seeds remaining in the straw that can sprout in your garden. Do not use hay for this purpose, as it is more likely to harbor seeds.
Mulched leaves
Leaves are a low-cost option for bed protection at the end of the growing season. They should be partially mulched first, as whole leaves can form layers that repel water. Avoid collecting leaves from the roadside during winter, as they may contain runoff road salts. This option works well in perennial beds and can even be used lightly in vegetable beds.
Paper
Rolls of undyed, unbleached, resin-free paper can be purchased at your local hardware store. This paper is usually marketed as a weed block or construction paper. It isn't a good option on its own as it tends to blow away and tear easily. It does, however, make an excellent base layer when establishing new beds and mulching around vegetables. Be careful not to overapply or use multiple layers, as this can limit water penetration.
Newspaper is less desirable as it can introduce unwanted contaminants from color inks and plasticized coatings. It can easily form a papier-mache-like layer when overapplied, preventing moisture from reaching the soil.
Bark
There are many types of bark available on the market. Shredded bark has a soft appearance and will break down more quickly. It is also less likely to wash away than other types, such as pine bark. It is one of the most common types of bark mulches in ornamental beds. Dyed and undyed options are available. Pine bark and pine bark nuggets are occasionally used due to their durability. Still, their light weight and thickness make them prone to blowing or washing away.
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Pine straw/pine needles
This mulch is standard in the southern United States, where pine tree forests are common. While it is harder to spread, it has a nice appearance and may be an option if you already have pine trees in your yard. While this can be used in the vegetable garden, it is more suited to other types of gardening.
Some products have been marketed as artificial pine straw mulch. These are shredded plastic and shouldn't be used in the garden.
While pine needles are acidic straight from the tree, their ability to acidify soil is negligible. You will not be able to adjust your soil's pH by applying them. If your garden has a high pH, you should not plant acid-loving plants such as blueberry and rhododendron. Instead, choose plants that are appropriate for the location.
Cardboard
While occasionally used as a base layer or in vegetable gardens, cardboard is less desirable than undyed paper. It can hold glues, staples and toxic dyes that you don't want in your garden. Corrugated cardboard can also harbor pests such as termites. If you are using cardboard, use only undyed, uncoated cardboard without any staples.
Inorganic mulches
Plastic
Plastic mulches offer a variety of benefits, particularly in commercial or large-scale vegetable production. Reflective mulches can repel thrips and aphids and reduce soil temperatures, while black mulch can increase soil temperatures. These are more often found in commercial vegetable production. Most are replaced seasonally, and biodegradable mulches are becoming more common. For more information on vegetable plasticulture, read “Plasticulture for Michigan Vegetable Production” by Michigan State University Extension.
Shredded tire
This is a waste product that isn't appropriate for garden beds, especially where food is being produced. Old tires can release problematic chemicals and heavy metals into the soil as they decay. They heat rapidly in the sun, stressing plants, and increasing the temperature in the garden. Not only do these metals pose a risk to humans, but they can also result in nutrient toxicity and uptake problems with plants in the landscape. Also of concern is the fire risk associated with shredded tires. Once lit, they can be very hard to extinguish.
Rock
Some specialty gardens, such as traditional Japanese gardens, make creative use of rocks. Rocks, however, aren't appropriate for most gardens, and certainly not in vegetable gardens. They hold and reflect heat throughout the day, don't add organic matter to the soil, and will still allow the buildup of leaves and organic matter, in which weeds can still grow. While rock can make an ornamental impact, it usually requires additional maintenance to keep tidy. Brick is occasionally used as a mulch and has similar features to rock.
Weed block fabric
These products are sometimes used as a base layer under other mulches in gardens. For long-term use, they perform this function poorly. Some are soft and made of spun polypropylene fabric, while others are more tarp-like in appearance. These can work well in vegetable beds as pathways, preventing the area from becoming muddy. When placed in perennial beds, they can become a nightmare. Over time, weeds and plant roots will penetrate and grow through the layers, making it impossible to remove without a serious amount of work and cutting. They also limit water infiltration, leading to soil compaction when used over long periods of time.
Remember that organic mulches break down at different rates, so they need to be refreshed periodically. For mulches like wood chips, a fresh coat each season will refresh the color, but you may not need large amounts. Straw, on the other hand, will break down quickly and in some cases, may require small additions the same season, primarily after it has settled. Inorganic mulches still break down over time. Plastic mulches will become brittle and tear, while tire mulches will crumble and produce dust.
Using mulch in your garden offers many benefits. They can enhance plant growth, reduce maintenance, and help combat weed proliferation. By selecting the right type of mulch for your needs, whether organic options like straw and wood chips or more specialized materials like plastic and paper, you can create a thriving environment for your plants while minimizing common gardening challenges.
