Basics of Garden Mulch

There’s something special about mulching a vegetable garden. As a boy, I can remember my father covering our entire garden in 8″ of clean straw every spring. Everything we planted seemed to thrive. I can remember the feel of walking barefoot on that mulch, as I helped to care for and harvest from that garden. Since that time mulch has become even more popular though those entering the gardening hobby often don’t understand it. First of all, let’s define mulch.

Mulch is anything used to cover the soil.

When we speak of “mulch” we often mean that whatever we’re using will decompose, though this is not always the case. Some use a plastic “mulch.” I’ve heard of rocks being used as a “mulch.” On account of our society’s love of big box stores most of us are familiar with the sacks of bark mulch they sell for home landscaping. Choice of mulch material often depends on both its intended purpose and availability. For instance, I would hardly consider using sacks of colored bark mulch in my vegetable garden. There are other materials which would do the job better and at less cost.

bark mulch, bagged cypress mulch
Bags of bark type mulch are available at box stores but are not usually the best for mulching a vegetable garden.

Why would a person want to use mulch in the garden?

By the mere fact of covering the soil mulch does several things.

  • It reduces weeds. Many weed seeds require light in order to germinate. By mulching the gardener prevents many weeds from ever sprouting in the garden.
  • A mulched garden retains moisture better than an unmulched garden. This cuts down on watering and on the dreaded¬†blossom end rot, which so often affects tomatoes, peppers and eggplant in moisture stressed gardens.
  • A mulched garden is easier to weed. This is so, not only because weeds in moist soil are easier to pull, but also because mulched soil resists compaction. Go ahead, mulch an area in your garden and then, after a few weeks take a peek under the mulch. You’ll be amazed at how much more friable it is!
  • Mulching a vegetable garden enriches the soil. So much so, that I rarely use fertilizer in my garden, nor do I remember my father doing much fertilizing. The annual application of mulch and other compostable materials, to the surface of the soil did the trick. Earthworms and other organisms pulled the mulch’s nutrients into the soil and made what was there available to the plants.
mulched tomato plant, mulch around transplant
Mulch is especially helpful for tomato transplants. It maintains soil moisture levels as well as preventing foliar disease caused by rain splashing soil up on the leaves.
  • Mulch helps regulate soil temperature. In the summer it can keep soil from becoming too hot. In the winter it helps keep it from getting as cold. I remember, as a kid, trudging over frozen ground and digging through the snow to our mulched bed of parsnips and being able to easily dig the roots for a mid winter feast.

Unity Home Group: The Complete Guide to Mulch

  • Mulch makes a garden more nature friendly and ecologically healthy. Mulched and healthy soil is home to many small creatures, many of which consume pests and enrich the soil itself.
baby box turtle, newborn turtle
Mulch makes a garden hospitable for harmless & beneficial creatures.

What can be used for mulch?

To conserve space I’ll limit this discussion to organic materials that decompose. By far, this is what is most commonly meant when gardeners extol the virtues of mulch. Many things can be used as mulch. Perhaps the most basic is simply to use the very weeds we pull, as we weed in the garden. This is an acceptable mulch, though it can be much improved if one first places some cardboard under the weeds. Several layers of newspaper or a sheet of cardboard will work splendidly, though it is a good idea to supplement them by placing weeds or some other material on top.

cardboard mulch, planting through mulch
Cardboard works great to suppress weeds and retain moisture. Notice the dead weeds piled on top.

Other materials which can be used for mulching a vegetable garden are: leaves, shredded paper (if there’s no plastic in it), and even wood chips. I’d be hesitant to use many wood chips in the vegetable garden. They take time to break down, can rob nitrogen from the soil while they are breaking down, and usually take a couple years to completely decompose. Newspaper makes good mulch, though it requires some other kind of mulch to weight it down. Remember, if you use newspaper, lay down a minimum of 6 layers, otherwise, you’ll blink… and it’ll be gone. Cardboard is the bomb! I can’t think of anything better as a bottom layer for mulch. Good cardboard lasts a long time and really does the job.

Materials to avoid when mulching a vegetable garden

Avoid anything that will remain in your soil and contaminate it. For instance, when I use cardboard, I strip off tape, plastic labels and staples before using it. If you have access to shredded paper, beware. A lot of times envelopes with plastic windows get shredded into the bag. If you use this shred for mulch, you’ll be picking bits of plastic from your soil forever!

I avoid the glossy and brightly colored pages (usually advertisements) in the newspaper. Last I heard they use soy based ink, but still, I remember when they didn’t, and those pages for a no go for mulch.

Years ago I mastered the ability of recognizing bags of grass clippings from a “speeding car,” and stopping to get them. My young wife thought I was eccentric for doing this. I no longer do this. The reason I stopped is that too many people use broad leaf herbicide on their lawns. Herbicide residual can be brought in with grass clippings, causing crop failures in the garden for several years.¬† The same is true of hay. It’s so sad, but unless I absolutely know that it’s from a field which hasn’t been treated for at least two years, I won’t use hay anymore.

herbicide affected foliage, tomato leaves herbicide damage
Herbicide damage usually looks as if the plant were made of plastic and then, … hit by a blast of heat, melting the leaves.

Finally, if plant material comes loaded with weed seeds, you might not want to use it as mulch. I don’t worry, too much, about weed seeds, but there are some weeds which are better kept away from the garden.

Do you have a favorite material for mulching a vegetable garden, one which I haven’t mentioned? We’d love to hear about it in the comment area below.

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