The Magic of Mulch

We at Spotts Garden Service spend a lot of time spreading mulch, which is basically anything you put over the top of your soil to keep weeds down and moisture in. We use shredded hardwood and straight compost most often to mulch our customers’ gardens, but we’ve used straw, sheets of newspaper, shredded leaves, and even cocoa hulls in our own gardens.

Wood chip mulch in an ornamental bed.

Why mulch? Mulch helps mimic the way nature build soil. In a forest, the leaves fall onto the forest floor, where microbes and worms eventually turn them into humus, the organic matter that goes into making soil.

You can use this same method for improving fertility in your garden. Apply mulch on top of the soil, and in a season or two, it disappears. Why? Because it has been broken down into the soil, where it loosens the soil structure, makes the soil more able to hold moisture, and boosts nutrients.

But that’s not the only reason to love mulch. Mulch slows down weeds’ ability to find a foothold in the garden. Weeds zero in on bare soil. Cover your bare soil, and you dramatically reduce the weeds’ target.

Properly employed, mulch helps your garden retain water and stay cool by acting as a insulating layer in summer. Applied in early winter, it insulates cold soil to prevent the constant freeze/thaw cycle that heaves your plants out of the garden.

Straw mulch is great for vegetable and strawberry beds.

For spring and summer mulching, wait until the soil warms (now’s a good time). When mulching in winter to prevent plant heaving, wait until the ground freezes, then apply your mulch.

Plan to apply 2″ to 4″ of the organic mulch of your choice. We recommend you steer clear of cypress mulch and other softwood mulches, including those made by shredding pallets. Softwood mulches tie up a lot of the nitrogen in your garden while breaking down, far more so than hardwood mulches do.

Dyed mulch–especially the red kind–really stands out in the garden. Unless you want your mulch upstaging your plants, stick to mulch that is similar in color to the soil.

Avoid putting mulch right up to the stems of plants; it can cause rotting. When mulching around trees, steer clear of the dreaded “mulch volcano” effect. Take a look at the tree trunk; it flares out where it meets the ground. That flare should never be covered with mulch.

You can refresh last year’s mulch by raking through it to fluff it up. If you see a lot of new weeds coming up, or if the mulch is now the consistency of soil instead of recognizably mulch, it’s time for a new layer.

Use mulch on the tops of your pots, too. While wood chips or straw work great on top of containers, you can also finish pots off with a layer of moss or pretty glass pebbles to give them a finished look that helps them retain moisture.

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About Amy Mullen

Amy graduated from DePauw University with a degree in physics, a lifelong love of theatre, and a problem-solving style that combines the approaches from both those fields. A Master Gardener and long-time communications professional, Amy conducts gardening seminars and blogs about gardening in addition to her work with Spotts.
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