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A seedling emerges from the ground, surrounded by mulch.

Mulching can help your plants weather a dry spell.

Mulch through hot, dry spells

By Nancy Rose

From eNews, July 5, 2007

Mulching is one of the best things you can do to help your plants through a dry summer. On hot days, bare soil heats up rapidly and soil moisture evaporates more quickly. But as little as an inch or two of mulch spread over bare soil can significantly lower soil temperature and reduce water loss.

There are many types of mulch for the home landscape available in two categories: organic and inorganic. Organic mulches include materials such as wood chips, bark nuggets, pine needles, shredded leaves, straw, grass clippings, and compost. Organic mulch breaks down over time, gradually adding nutrients and improving soil structure. Inorganic mulches, which include pea gravel, crushed rock, and landscape fabrics, will help hold soil moisture but are often more difficult to apply or remove and do not add to the soil.

What to choose? Think about your landscape situation. Coarse mulches that decompose slowly are ideal for landscaped areas that are rarely disturbed with digging. Mulches that break down more quickly are best for planting areas like vegetable and annual gardens where the soil is worked up annually.

Here are some specific recommendations:

Trees and shrubs (individual or group plantings): Apply 2 to 4 inches of coarse, long-lasting mulches like wood chips or bark nuggets.

Perennial flowerbeds: Apply 2 to 3 inches of finer mulch such as shredded leaves, pine needles or cocoa bean hulls. Coarser mulch can be used around perennials that are rarely dug and divided.

Annual flowerbeds: Apply 1 to 2 inches of attractive, fine-textured mulch such as cocoa bean hulls or finished compost.

Vegetable gardens: Apply 2 to 6 inches of fast-decomposing mulch such as straw, hay, grass clippings, partially decomposed compost, or shredded leaves.

Bagged or baled mulches are available at nurseries, garden centers, and home improvement stores. Also check with your municipality--many offer mulch and compost products to local residents.

For more information on mulching trees, shrubs, flowerbeds, and vegetable gardens, see "Mulching the Home Landscape" or "Mulch Vegetables FAQ."

Nancy Rose is a horticulture educator with University of Minnesota Extension.