Some words freak us out. Everyone thinks "moist" is weird. "Kiddo" is creepy, especially when someone who doesn't have kids uses it to refer to yours. But around here, "mulch" is the winning...loser. Which is pretty sad, since, in spite of its gross-sounding name, mulch is one of the gardener's biggest superheroes—at least during summer, when the weather heats up, and the weeds get sassy. So let's grit our teeth and talk about why you should be plotting your mulching strategy!
Okay. "Plotting" is a pretty nasty word, too. Sorry about that.
Why is Mulch So Important?
Starting plants from seed, indoors or out, is probably one of your favorite gardening activities. Or maybe it's harvest time when you enjoy the summer's first ear of corn or the early melons you've babied all season. But what about all that in-between time, when you're not picking flowers or getting all zen about pruning your roses? We're talking about weeding, watering, and pest control.
Mulch reduces the amount of time you'll spend messing with the sucky side of gardening. Here's how mulch helps us maintain our sanity:
- Regulates soil temperatures: Mulch serves as an insulating layer, preventing the soil from overheating in summer, and increasing heat absorption in early spring and fall.
- Reduces moisture loss: Curb evaporation with a layer of mulching material to retain soil moisture and protect it from the drying effects of moving air and direct sunlight.
- Suppresses weeds: Mulch will discourage weed seeds from taking hold in your beds, and "starve" young weedlings (we made that up) by depriving them of sunlight.
- Prevents soil erosion: The same weather-protecting benefits reduce topsoil loss and help stabilize slopes.
- Discourages pests: Some mulches repel ground-dwelling insect pests, and others leave pests exposed to their natural predators.
What Kind of Mulch is Right for Your Garden?
Gardeners who've had bad luck with mulch probably didn't know some of the details most of us miss. Every kind of mulch, whether it's organic or petroleum-based, has its pros and cons. The cons tend to win out if the material isn't used correctly, but when it's used in the right manner, the benefits can be huge.
In the fall, deciduous leaves turn to gold. Gardener's gold, anyway. Hoard as much leaf litter as possible. It's great for your compost pile, but the leaves also serve as an overwintering "blanket" for perennials, and a magnet for red wiggler (Eisenia foetida) worms, the kind farmed for worm poop. Keep a thick layer of leaves on your beds until you're ready to work the soil in spring.
Straw mulch is a low-effort, high reward mulching material. Dump a layer four to six inches deep for best results. It rakes up easily when you need to work the soil, and you can move it aside to transplant seedlings. Its light colors reflect heat, and its hollow stems trap air, aiding in insulation and temperature regulation.
The trick with straw is knowing where it came from. Some of the pesticides and herbicides applied to the crops from which straw is sourced will leach from your mulch and harm your garden. Here's a fantastic blog post from The Compost Gardener with great information about the half-life and hazards of common chemicals, and how to quickly test for them in your straw. You can apply these tips if you plan on adding animal bedding straw to your compost pile, too.
Newspapers and cardboard
If you've ever built raised beds, you probably know about putting down a few layers of cardboard under your ground cloth before filling up your planter boxes. You can also wet down (moisten!) cardboard and place it over or in between your veggie rows. Those round cardboard discs that come with your frozen pizzas? Cut a hole in the middle through which you can plant a new shrub, or if you cut a slit to the center ring, you can place it around the base of a growing plant.
Several layers of newspaper will do the same thing. Since most inks are soy-based, newspaper is a safe and cheap mulch. And if appearance is important to you, cover it all up with bark chips. Or maybe glitter.
When most people think of weed suppression, they think of the rolls of perforated plastic sheeting available at any hardware store. Yeah, that thin, flimsy stuff. Save it for your next Halloween costume, or gift it to your neighborhood goth. It's worthless, in our book. In fact, all the perforated plastic sheeting on the market won't last very long, since weeds will grow up through the holes, and seeds will sprout on debris accumulated on the surface. One way we do think it shines is under raised beds, but only if it's folded over several times.
We recommend you shop where the pros go—a commercial landscaping supplier or bulk rock and mulch yard—and get the thickest stuff available. That way, when it starts to fall apart or get pinned down by weeds, it's easier to pull out in larger chunks.
Wood or bark chips
Speaking of bark chips...cedar and cypress wood products have a reputation for deterring insect pests. In spite of eucalyptus' fame as a flea deterrent, the jury's still out as to whether it inhibits plant growth, so we caution you to review this study from U.C. Davis before ordering a truckload or two.
Avoid using dyed "beauty bark" in your veggie garden. Not only are the dyes questionable, but the chips are most often made from recycled, treated wood: Defective lumber, wood pallets, or worse. Contact a local tree service and ply them with booze, fresh veggies, and a bit of cash, or get your own portable wood chipper if you do a lot of pruning or windfall cleanup at home. Wood chippers are also fantastic for chopping up compostable materials. If you have an annoying neighbor, well...we've all seen the original Fargo movie, right?
As with straw, lay on four to six inches of wood and bark mulch. It will look like a lot, but it'll soon settle and compress.
Each spring (and sometimes fall) sheep line up for shearing. Ideally, the wool comes off in a single fleece. In larger operations, the shearers bale up the wool to be processed for sale on the commodity market, or homestead-scale shepherds clean and trim the fleeces by hand, trimming off the unusable margins. Wherever it's sourced, "waste wool" still has value. Sometimes, it's felted for crafts or organic, low-VOC insulation, or turned into biodegradable mulch material. You can buy pelleted, woven, or felted wool, or hit up a local shepherd for their trimmings.
Our homesteading friend Michelle, who shears her own small flock, uses entire waste fleeces around her fruit trees and berry bushes and mats up smaller bits for heat-sensitive veggie plants. She's also used it under growing melons to prevent fungus and rot; fleece is naturally antimicrobial. "I'm really awful at hand shearing," she said. "So I have a lot of waste wool, and some seriously funky-looking sheepies." Still, in spite of some misconceptions spread by extreme animal rights groups, the shearing process is ethical and humane—even on a commercial scale. It's also organic and compostable.
Marketed as a "green" product, presumably because nobody really knows what the hell to do with old tires, shredded rubber mulch is probably our least favorite option. Unless, of course, your idea of a gorgeous backyard is a mid-July Wal-Mart parking lot. Writer Steve Bender's take on shredded rubber mulch mirrors our own opinion. Read his hilarious-yet-sobering Southern Living article and decide for yourself whether or not you want the olfactory (or full-on) equivalent of a tire fire in your garden this summer.
Gardeners feel gut-punched at the thought of using plastic of any kind, other than the containers that come home with their store-bought plant starts. (Which is another reason to grow your garden from seed!) The thing is, high-quality plastic sheet mulch will last a long time and reduce water waste, and all but eliminate your need for herbicides. We're not fans of using sheet plastic mulch under landscaping bark or rocks, though, since it will collect soil and encourage weeds to grow on top. It's best for lining linear vegetable garden rows and pathways where you don't need to water.
Make sure weeds aren't growing through any tears or holes in your plastic sheet mulch. Sweep off accumulated soil, and consider adding newspaper (six to 12 sheets) or cardboard underneath for long-term applications.
Start With a Clean Slate
Unless the soil beneath your mulch starts out weed-free, simply covering it up won't suppress your problems. You're a freaking gardener, not a politician! You've got to destroy as many weeds and weed seeds as possible to achieve a successful mulching strategy. First, remove all visible weeds. Pull them out by hand, or hoe them out by the roots. Then decide which of the following approaches—alone, or in combination—suits your gardening philosophy:
Till your garden under. This will bring buried weed seeds to the surface and encourage them to grow. Then, after hand-weeding, let a second wave of weed seeds emerge, and till it again. You want to make sure you've let as many seeds germinate as possible before you knock them down.
Apply a pet-safe herbicide. Pendimethalin targets pre-emergent weeds. After you apply it to the topsoil, keep everyone away from the area for a couple of days to be safe, and hold off on planting for a couple of weeks.
Cook your weed seeds through solarization. Thoroughly moisten the soil with water, cover it with 4-millimeter clear plastic sheeting (staked down along the edges) and let the solar oven effect take over. According to the Texas A&M AgriLife Extension, this might take about four weeks in the middle of summer. We suggest leaving it on longer since your summer growing season will be shot, anyway. Solarization, preceded by complete removal of plant matter, is our preferred method for gardeners creating new garden plots.
Napalm your entire property and move to the moon. No weeds on the moon, as far as we know.
All of these techniques, to one degree or another, damage your soil's delicate ecosystem—including beneficial bacteria, fungi, and nematodes—but you can always dig in mature compost to jump-start new life.
At Seed Needs, We've Got Your Garden Covered
Mulch really does work beautifully on well-prepared garden beds. Choose the type that works best for you, lay it on thick, and replenish or replace it as it naturally breaks down.Use all the plastic and rubber mulch you want—we'll balance out the bad karma with our healthy, disease-resistant organic plant genetics. We offer the freshest, highest-quality seeds available. Can't find what you're looking for in our catalog? Contact us to find out if we'll be refreshing our stock! Since we only carry enough seed we can expect to sell in a single season, we often run out early, but there's always the chance we can accommodate special orders and quantities. We're a growing business, in more ways than one, so your feedback and suggestions help us better serve you, and plan ahead for next season's gardens!