A garden mulch strategy is a must for many reasons, but it's especially vital during a hot, dry summer like the one we're currently sweating through. Under drought stress, veggie plants produce lower yields and flowers bloom for a shorter time. Bugs and other pests are more likely to attack a stressed plant, too. Our lawns and gardens are experiencing conditions like never before, making it even more important to do everything you can to retain moisture. The National Oceanic and Atmospheric Administration just announced the first half of 2012 was the hottest ever recorded, meaning it's prime time for drought-proofing your lawn and garden.
Luckily, garden mulch derived from organic (often free) materials like grass clippings, leaves, and pine needles will stifle weeds, retain more moisture, and cool the soil, which in turn conserves water, as well as build soil fertility, which is the basis for organic gardening. And let's make no mistake, mulching also makes a gardener's life a whole lot easier.
Pioneering gardening author, the late Ruth Stout, considered the godmother of mulching, certainly made no secret of it. She preached the benefits of mulching, including less human labor, in the classic The Ruth Stout No-Work Gardening Book, and later in Gardening Without Work: For the Aging, the Busy, and the Indolent. The good news? It's never a bad time to mulch. So if your veggies plants are currently growing in bare soil, get some garden mulch down! The average backyard gardener can likely gather enough organic material from his or her own yard, says gardening expert Fern Marshall Bradley, author of Rodale's Vegetable Garden Problem Solver. All of the benefits of mulching—the fact that mulching prevents weed seeds from germinating, and makes it easy to pull out the ones that do survive; that it improves soil health that helps soil-dwelling microorganisms and earthworms boost plant health; and that it keeps your veggies dirt-free—make your life as a gardener that much easier.
Here are the ins and outs of different types of garden mulch for veggie gardens:
While it is a good idea to leave grass clippings in your yard to improve lawn health, you don't need to do that every time you mow. Bradley suggests collecting grass clippings from your untreated lawn two or three times a year, and using them as vegetable garden mulch to provide a natural nitrogen injection that will help your veggies thrive. You can even collect from neighbors—just make sure they don't use lawn chemicals.
When leaves drop in the fall, drive your lawn mower over them to chop them up. Bag the chopped leaves (if your mower has a bag collecting them, that will save you some of work), and spread them as vegetable garden mulch in the spring. Bradley warns against using whole leaves as a mulch. They could form thick mats that might restrict water absorption.
While compost alone isn't the best mulch because once it dries out, beneficial microorganisms are lost, Bradley says you can put down an inch or so of compost and then top it off with grass clippings to keep conditions ideal. Just be sure if you purchase compost or get it from a municipal facility, you know what it was made from—some places use human sewage sludge (something prohibited in the National Organic Program), and some municipal compost could contain herbicide residues that can kill your plants. To do a test on compost, fill a tray with it and plant a few annual seeds. If seed germination rates are poor, or if seedlings look sick, the pH of the compost could be poor, or it could contain pesticides. Either way, you don't want to use it on your garden.
Straw and hay
These are great mulches, just make sure you are getting weed-free straw or you'll wind up defeating the purpose of tamping weeds down with mulch. Organic Gardening magazine warns against putting straw or hay right up to the base of your plant stems, though, since that can creating inviting conditions for slugs and other garden pests.
Some gardeners think that using pine needles as a mulch will make the soil too acidic for some plants, but you'd have to apply a whole lot to cause that kind of soil composition shift. So, use them!
Black and red plastic mulches come in rolls and can be laid down to suppress weeds; they're particularly useful when growing warmth-loving tomatoes and eggplants because they warm the soil underneath. However, these mulches are not a very sustainable option. Plastic comes from petroleum, and more and more research finds that when it's heated (say, in the sun), chemicals leach out of the plastic. We recommend organic garden mulches because they add to soil fertility.
Heavy paper mulch rolls are sold in some gardening centers to suppress weeds, and Bradley says they do the job if you are dealing with a particularly tough weed infestation. Recycled paper mulch is a more Earth-friendly option because it converts landfill-bound paper and avoids killing trees for mulch. However, scientists have found that recycled paper can be contaminated with the harmful chemical bisphenol A, or BPA. Again, we think it's best to stick with organic materials like grass clippings, chopped leaves, and pine needles. Plus, these things are often free and available in your own backyard!
A few rules of garden mulching…
• Always weed an area before you put mulch down.
• When applying the mulch to your garden bed, take care not to pile it around the stems or crowns of plants. Wet mulch can cause them to rot.
• When using organic mulching materials (like grass clippings), don't be stingy. A layer that's too thin will allow sunlight in and won't suppress weeds, and it will allow moisture to evaporate, increasing the amount of watering (a.k.a. work) you'll need to do. Areas in full sun may need four inches of mulch to keep weeds at bay. For shadier, less troublesome spots, two to three inches should suffice.
• Reserve wood-chip mulch for your flower garden. The large chucks take a long time to break down, and can interfere with the frequent planting and harvesting of annual vegetables. (Just don't put wood-chip mulch up against your house. You don't want a termite problem!) You can also use this type of mulch in your garden paths, but we recommend avoiding dyed mulches that could contain harmful chemicals.
• Don't sweat a weed here or there. "It's not necessary to have a completely weed-free garden, but mulch helps to keep them under control," says Bradley. If you see a weed emerging, just toss more mulch on it to knock it out without resorting to harmful chemicals.
More ways to drought-proof your lawn and garden:
Be water wise. Before you pull out that watering can, grab a screwdriver. Colorado State University Extension experts recommend checking moisture levels by inserting a 6-inch screwdriver into the soil. If it can be easily inserted, you don't need to water your garden beds. For the best water efficiency, water in the evening or early morning before the high heat of the day hits and causes more rapid evaporation. When you're trying to figure out when to water your lawn, look for footprints. When footprints or mower tracks are easily indenting your lawn, it needs a drink. Use organic gardening tips to learn how to create a lawn that locks in moisture and reduces runoff.
Go native. Plants native to your area are less fussy and help support pollinators native to your area. Visit the Lady Bird Johnson Wildflower Center for state-specific native plant suggestions. New flowers will need to be watered regularly during the first two weeks, but then you can gradually cut back. When planting native trees, apply a 3- to 4-inch thick blanket of mulch at least 2 feet around the tree base—just be sure to keep a 2-inch space between the tree trunk and the mulch.