Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client's Request: I am very excited because I just built some new raised beds for vegetables in my back yard. Previously, I have used mainly Earth Boxes and miscellaneous pots. But with the new garden area, I was wondering how best to mulch. In previous times, I used lawn clippings - available free in my yard or from my neighbors. Now, my lawn is gone along with many others of my neighbors. I do have an abundance of last year's oak leaves, but I wondered if they might not be good for the plants. What is your opinion of using newspaper? Is hay (or straw) a good choice? Though I would have to buy that. Other suggestions?
Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your question about mulches. Most mulches help suppress weeds and retain moisture. Organic mulches (plant based) will decompose slowly and add nutrients to the soil. It is important to note that because soil organisms use nitrogen as they decompose the mulch, it should be used only on the surface to avoid nutrient deficiencies. Nitrogen eventually returns to the soil as organisms die.
For garden areas that are worked annually (your vegetable beds, for instance), it is best to use mulches that break down rapidly, such as rice straw, dried grass clippings or alfalfa. Oak leaves would be good to use for this, as long as they don't get matted down and prevent water from passing through. Shredding the leaves by running a lawn mower over them would prevent the matting if you experience the problem.
Newspapers could also work, but we wouldn't use them as a stand-alone mulch. You may need to shred the newspaper some so that they aren't subject to matting. Newspapers can also easily blow away and looks a bit unsightly. You could layer another mulch material over it if you do choose to use it.
Straw is good for vegetable gardens. It is light weight and will break down over time. Make sure you use straw which shouldn't have weed seeds, while hay often contains copious weed seeds.
You want to stay away from bark or wood mulches because they take a long time to decompose, and you will need to rake them off whenever you change your vegetable crops.
To help in your decision on which mulch to use, I've attached a summary of the various types of mulches with their pros and cons. Please let us know if you have further questions.
Happy gardening!
Help Desk of the UC Master Gardener Program of Contra Costa County (SEH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/).
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