For those of us who are now raking leaves and fussing about keeping our lawns clean, it’s interesting to step back and see “lawn debris” as having a purpose. I suspect Mother Nature actually has a plan in laying down her leafy blanket before winter arrives. For example, the layers of leaves create an insulating blanket for winter over the small seedlings of the forests. When warm weather returns, these leaves break down to enrich the soil. We can emulate nature by mulching our plants and help protect them for the coming winter.
Various Roles of Mulch
Mulch has other important roles besides insulation, however. A heavy layer of mulch conserves moisture in the garden to help plants survive hot and dry summers. Mulch is also a tremendous aid in smothering weeds. When gardening, I much prefer to concentrate on vegetables than spending time and energy weeding. Continual mulching also improves the soil’s structure and fertility. We are rewarded with more nutritious and tasty produce when there’s mulch to provide constant nutrition for plants.
Another benefit of mulch is to keep vegetables off damp soil and thereby prevent produce like cucumbers and tomatoes from getting dirty and even moldy. Additional mulching before winter prevents roots and bulbs from freezing and the soil from heaving and disturbing roots.
What Materials to Use
Mulching, like composting, is a basic practice of organic gardeners. We might think of “organic gardening” only as gardening without chemicals. Just as importantly, however, organic means using “carbon compounds,” or materials from animals and vegetables for mulch and fertilizers. Therefore, mulching is usually done with materials like grass clippings, shredded leaves, hay, straw, compost, sawdust, shredded corn cobs or newspaper. Some people also use polyethylene products for mulch. I don’t use those because they’re made from petroleum, and I also dislike the waste they create. I’d rather use materials that break down and enrich the soil and therefore don’t need me to clean them up!
On our homestead, “mulch” and “compost” are often synonymous. By hauling compost now to the growing paths in the garden, I am ready to put out seedlings next spring when the temperature permits. This was a life-saver last spring when the rains seemed continuous and mud prevented me from hauling a heavy cart. I can always add more compost (“mulch”) again when the rains stop.
Balancing Different Mulches, Pros and Cons
It’s important to know about the “down-sides” of different mulches so we can compensate for them. For example, materials that are high in carbon will actually “rob” nitrogen from the soil as they break down. These materials include alfalfa hay, shredded corncobs or corn stalks, newspaper, sawdust and straw. They’re still great mulches to use, but you’ll want to add extra nitrogen to the soil with compost, manure or blood meal.
Grass clippings are usually plentiful, but if they’ve gone to seed, we’ll be punished by having grass to weed out of our gardens. Grass clippings and leaves tend to mat and prevent rain from entering the soil. Shred leaves several times with a lawn mower and add straw to dried grass. This makes both leaves and grass excellent mulches.
I don’t use fresh manure for mulch because it burns garden plants and it introduces weeds. Once manure is composted, however, these drawbacks no longer exist.
Eight to 10 sheets of newspaper does a good job of smothering weeds. I think newspaper is ugly in the garden, so I put other mulch on top of it. Don’t use any glossy sheets. These contain chemicals that aren’t good for plants or people. If you have a good supply of newspaper and use it regularly, your soil will become acidic. Check the pH of the soil and add lime to balance the pH if necessary.
Two potential mulches that I’ve never used but I have heard warnings about are peat moss and sunflower hulls. Peat moss blows away when it dries and is difficult to remoisten. Additionally, it’s expensive and doesn’t add any nutrients to the soil. And if by chance you have a big supply of sunflower hulls you were going to use for mulch, don’t. They contain chemicals that stunt or even kill plants. Maybe that’s nature’s way of keeping the weeds down where sunflowers grow?
A Couple Precautions
Now that I’ve gotten you all enthused about mulching, let me add a couple caveats for the next growing season. Eager as you may be, don’t mulch your garden too early when the soil hasn’t yet warmed. You will delay the growing season by keeping the soil cool. For those interested (and I am), a soil thermometer will tell us when it’s time to plant tomatoes (soil at least 60 degrees Fahrenheit) or corn (soil warmed to 70 degrees). Once the soil is warmed, get that mulch on!
Secondly, never mulch dry soil. Mulching when the soil is dry prevents rain from penetrating. Mulching after a rain or a good watering helps retain soil moisture.
Finally, don’t apply dense mulch close to the roots of plants. This can encourage fungal problems. I believe that placing thick mulch up against seedlings also makes it easier for slugs to attack the plants.
Before winter arrives, what should we be doing to protect our perennial flowers, bulbs and vegetables? Ideally, apply a thick layer of organic mulch around and over them. This will insulate the soil and prevent a deep freeze. The soil will therefore not heave or become compacted and non-friable.
Remember, you’re also tucking precious earthworms in for the winter. They will really appreciate a layer of shredded leaves covered by straw, and will return the favor by aerating you soil next year.