Should I Sheet Mulch My Entire Yard At Once?

Asked February 18, 2020, 5:52 PM EST

I bought a house this year with a 4000 sqft backyard that is overgrown with grass, weeds and clusters of poplar saplings from a large overhanging tree in the neighbor's yard. The yard is also full of overgrown trenches/in-ground garden beds from the last time it was gardened (about three growing seasons back according to the neighbor). The soil does appear to be dark and rich, but I have not tested it yet. I was considering just sheet mulching the entire yard with cardboard and wood chips before Spring (i.e. now) and starting a few garden beds close to the house. The plan is to eventually rework the entire yard into organic gardens and native plants (I also enrolled in the backyard habitat program last week). Is sheet mulching the whole yard a feasible way to control the weeds, grass and saplings that will inevitably be sprouting up this Spring and Summer? If not, are there any other techniques you suggest for controlling the weed growth and preparing the yard?

Multnomah County Oregon

1 Response

This is a large space to tackle at once. You might envision a blank slate to design and plant all at once. But, weeds grow through mulch, and seeds sprout on top. Consider dividing it into zones rather than an all-at-once approach. This is a suggestion, not a scientific-based fact, though.
The Extension Service has useful resources to help you decide what to do.
Sheet mulch has drawbacks. Here's information from WSU: "The myth of paper-based sheet mulch" https://s3.wp.wsu.edu/uploads/sites/403/2015/03/newspaper-mulch.pdf
The sorts of weeds you want to control are also a consideration. One option is to mow the grass regularly to keep weeds from flowering/seeding while you plan. Another possibility is mulching heavily with organic material to kill the grass and most weeds. Perennial deep-rooted weeds and saplings won't likely be killed by mulch. You'll need to remove them manually or chemically. Check out the WSU publication about using woody mulch, like arborist chips. "Using arborist wood chips as landscape mulch" http://pubs.cahnrs.wsu.edu/publications/pubs/fs160e/
Check out this article "Two ways to uproot your lawn", https://extension.oregonstate.edu/news/two-ways-uproot-your-lawn
After studying these options, ask more questions. Here, or call the Metro Master Gardener Volunteers to visit about your plans. https://extension.oregonstate.edu/mg/metro/have-gardening-question