在city租的菜地里看到有人用grass clippings 防杂草，目前看来挺有效的。
这个link介绍了Organic Weed Control Methods ~ Mulching， 其中也提到 lawn clippings http://faq.gardenweb.com/faq/lists/weeds/2005083919029708.html
"Lawn Clippings: Grass clippings are best used after they've been allowed to dry. If applied while they're fresh they can compact and generate heat while decomposing. They can produce strong odors the first week or two of decomposition but the scent will subside after that. It is not recommended to use grass clippings from lawns that have been treated with pesticides, fungicides, or herbicides. "
这个link 具体的教怎么做 - http://homeguides.sfgate.com/use-grass-clippings-weed-barrier-22097.html
