The Magic of Mulch

This bok choy will thrive thanks to the layer of mulch that protects the roots and keeps the soil moist.


I’m never one to believe fantastic claims made for most garden products. There’s no magic potion for plants that will guarantee a bountiful harvest. There is however, one thing that comes awfully close – mulch. Pound for pound, mulch is one of the best things you can do to prepare your garden for the growing year. Want proof?

  • Mulch helps hold moisture in the soil, something every gardener in the Southwest can appreciate.
  • Its protective matting helps prevent soil erosion during violent storms.
  • It gradually breaks down and provides a natural slow-release fertilizer, eventually helping to loosen the soil.
  • Mulch also keeps down the weeds that compete with your plants for food and water.
  • As a bonus it gives any garden bed a “finished” look.

What Mulch to Use?

There are dozens of materials available for mulch. The most common is shredded hardwood, a mixture of wood chips from a variety of trees. The exact mixture varies from region to region, depending on the trees nearby. Another category is shredded bark. Bark is usually cheaper but it has one drawback. Some barks are hydrophobic (resistant to water) and may float away during heavy rains. Whatever you choose, consider how well it protects and what it will add to the soil.

Mineral mulches such as crushed stone, gravel, or volcanic rock are sometimes used as a low maintenance alternative to organic mulches. Minerals won’t need replacement for several years but they also won’t add nutrients to the soil.

Pine bark looks good as a mulch but may not stay put during heavy rains. Many bark chips resist getting wet and float too easily.
How Much Do You Need?

Most experts recommend applying mulch in a layer about 3 to 4 inches deep. Bulk mulch is sold by the cubic yard, which covers 108 square feet at 3 inches deep. Bagged mulch usually contains 2 or 3 cubic feet of material, which at 3 inches deep would cover 8 to 12 square feet. Putting this all together, if you have 300 square feet of garden to cover, you need about 3 cubic yards of bulk mulch or 25-37 bags of mulch, depending on the bag size. If you’d rather not do the calculations, here are a couple of handy links that will do it for you:

Landscape Mulch Calculator
Scott’s Mulch Calculator

Tips For Applying Mulch

Whichever mulch you choose, begin application by removing unwanted weeds or grass. Then spread your mulch material around plants and shrubs into a 3-4 inch layer. A thinner layer of mulch will break down too quickly and not be deep enough to provide the protection your plants need.

With a shovel or your gloved hands – you don’t need splinters in your fingers – spread the mulch around, including under shrub branches to protect the roots near the central trunk. Don’t pile mulch against the trunks of trees or large shrubs in a conic volcano shape. Having moisture-retentive mulch against the outer bark can foster bark rot, which can damage or kill the tree.

Want a healthy garden this year? There’s no magic potion that can guarantee this but a layer of mulch will certainly come close.

This garden bed at the Dallas Arboretum will remain healthy through the searing Texas summer, thanks to its layer of mulch.
(Visited 382 times, 1 visits today)