Released May 22, 2008
LAWRENCE, Kan. - Plant advocate Jennifer Smith admits that mulching is one of her least favorite garden activities. It´s time-consuming. Typically, it´s a dusty job.
"Spread correctly, though, mulch can reduce your work in the garden season-long. If applied by late spring, mulch also has important benefits for plants, reducing their weather-related stresses and weed competition," said Smith, a horticulturist with Kansas State University Research and Extension.
In theory, mulch can be any protective soil cover, she said, ranging from black plastic to rocks.
"For the fewest problems and best outcomes, though, you need to use an organic mulch, such as wood chips, straw or shredded leaves," Smith advised. "Yes, organic mulches do break down over time. By doing so, however, they also improve the texture and nutrients of the soil underneath."
The horticulturist said that getting the most from mulch requires following two rules:
- Always keep mulch layers a few inches away from the base of plants, including trees.
- Keep mulch replenished, as needed, to maintain the proper depth - The coarser the material, the thicker the recommended layer.
To keep fine-textured peat moss or well-dried (herbicide-free) grass clippings from forming a water-blocking mat, apply them no more than 1 inch deep. Typical wood chips perform best in a 2- to 4-inch layer - especially if they´re on top of a layer of newspaper. Big bark chips only begin to serve mulch´s functions at 3 inches deep. A mulch layer of 4- to 5-inches deep can block the air supply to the soil.
"I like matching the mulch to its use," Smith said. "If you use straw in a vegetable garden, you can plow it in late next fall, enriching the soil. But, something longer lasting can be better around shrubs."
A 3- to 4-feet-wide mulch "doughnut" can save young trees´ life, she added. Mulch that´s up to or on their trunk harms trees. But, the protection of a mulch ring helps prevent trimmer and mower damage.
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http://www.oznet.ksu.edu/news/
Contact: Mary Lou Peter-Blecha, mlpeter@ksu.edu
