More about mulch

Continued from last week

Some precautions to think about: Do not use leaves or other treated organic materials as the pesticide residues can affect subsequent plant growth. Avoid using leaves or other organic materials that have diseases or insect problems as these can spread to other parts of the yard or garden. Maple leaves can add as much as 2-3 percent nitrogen and don’t seem to have any drawbacks. Like oak, cottonwood leaves are higher in tannins than most tree leaves, but adding small quantities of shredded cottonwood leaves mixed with other materials as mulch should not be a problem. Adequately composting yard materials is a good way to reduce harmful impacts. Shredded leaves (or other materials) are more desirable than unshredded materials. Shredding helps with decomposition and the increased surface area helps keep leaves in place (as they are less likely to blow away). If materials are not shredded, depending on how thick and compacted they get, they can form barriers that block water and oxygen movement in the soil. If there are only a few trees in the yard, consider shredding leaves and leaving them in place on the lawn using a mulching mower which can be more effective than leaving the leaves in place as is.

It is interesting as I lean on my rake for the umpteenth time this fall collecting and spreading leaves in my garden that I am adding a great soil building product to my soil. Alternatively, my neighbor recently purchased a machine that he drives around his yard which picks up leaves and shreds them. I can have all that I can get from him at no charge.

For answers to gardening questions, contact the Master Gardeners at the WSU Grant-Adams Extension office at 754-2011, ext. 4313 or email your gardening questions to ga.mgvolunteers@wsu.edu. Visit our web page at grant-adams.wsu.edu.