Coverting weedy lawn to food gardens, best cover crops to aid soil building?

Asked February 18, 2013, 2:06 PM EST

I have been letting my Longmont lawn die off for a couple of years and want to convert the entire area to food production. To help reduce weeds and improve soil structure I am considering a cover crop. The lawn is sloped to the sw, so will be building low walls to level into terraces, but want to begin improving existing soil in the meantime. Do you have any specific recommendations for this application? Thanks!!

Boulder County Colorado fruits and vegetables sustainable gardening and landscaping cover crops horticulture

1 Response

If your lawn has been in place for 10 years or more, the soil probably has a decent amount of organic matter in it. NOTE that just "letting the lawn die" could backfire...if you have KY bluegrass it will just go dormant, awaiting some moisture to regreen. You may want to consider killing the lawn while it is green and actively growing this spring with glyphosate (Roundup and other trade names; follow label directions).
There is no cover crop that would work well that you could plant now. Generally, cover crops are planted in fall and then small plants are tilled or spaded into existing soil in spring. If you wait too long in spring to till plants under, they get large enough to "gum up" a rototiller.
Whether you kill lawn grass with glyphosate or not, suggest that you add organic materials (soil amendments) to the soil this spring and rototill them in, mixing well, to a depth of 8-12 inches. If you don't kill it in advance, some bluegrass may survive this rototilling.
Suggest you avoid using more than 1 inch depth (3 cu yds/1000 sq ft) of manures or composted manure as your soil amendment. Manures often have a high salt content; this can damage roots of your food crop plants.

In fall (mid-Sept - by Oct 1) you can sow winter rye or winter wheat as your cover crop.

More details:
http://www.cmg.colostate.edu/gardennotes/244.html
http://www.ext.colostate.edu/pubs/garden/07235.html
http://www.ext.colostate.edu/ptlk/1848.html
http://www.ext.colostate.edu/ptlk/1616.html
http://www.ext.colostate.edu/ptlk/1607.html