We have endured multiple years of drought, and are probably in store for more. For many of us, it makes sense to replace all or part of our lawn area with less water-intensive plantings.
If you decide to undertake a lawn replacement, make sure you do it properly; incompletely killed grass can regrow amid new plantings, ruining the appearance of your new landscape and creating a maintenance nightmare.
The following three steps will lead to success.
Step One: Observe and plan. What existing trees and plants do you want to keep or remove? What are the sun and shade patterns within your yard? What types of grass grow in your lawn? Do you want any additional amenities, such as paving or a shade structure? How will you irrigate your new plants?
Step Two: Kill your lawn. Homeowners can use two eco-friendly methods to kill their lawns: Solarizing or sheet mulching. For detailed instructions on solarizing, see http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74145.html.
For instructions on sheet mulching, see Sheet Compost Your Lawn Away – The Real Dirt Blog – ANR Blogs (ucanr.edu) Solarizing uses the sun’s radiation to kill lawn grasses as well as many common annual weeds, harmful soil microbes, and seeds down to a depth of 4 to 12 inches in six weeks. Most beneficial microbes survive, including earthworms.
Solarizing requires six hours per day of full summer sun and takes 4 to 6 weeks to complete. It works best on fescue, ryegrass, and bluegrass, with partial success on Bermuda grass. Solarizing must be completed before new plants are installed.
Sheet mulching kills weeds by starving them of light. It takes 6 to 10 months and can be started any time of the year as long as at least three months of growing season are included. Sheet mulching works in sun or shade, and is effective on all grasses, including Bermuda grass, and many annual and perennial weeds. It is left in place permanently; over time, the dead lawn, sheeting, and mulch will break down into soil-enriching compost.
Sheet mulching should be placed before new plants are installed if being used alone to kill lawn or weeds. It can be placed after plants are installed if solarizing has been completed first. New hardscape and irrigation should be installed before commencing solarizing or sheet mulching.
A third option for lawn removal is to dig or scrape out the lawn. Be warned, however, that this method will not kill Bermuda grass and most perennial weeds, which have deep roots that will re-sprout. If you choose to dig out your Bermuda grass lawn, be sure to follow up with sheet mulching to prevent aggressive regrowth of the grass.
Step Three: Replant. Whichever method you choose to kill your lawn, time it so that you are ready to replant in the fall, winter, or early spring. The cool temperatures and moist soils of our wet season allow drought tolerant plants to develop the healthy roots they need to thrive with little water during the heat of summer. Taking time to thoroughly kill the grass and waiting until the climate conditions are suitable for new plants will ensure the long-term success of a lawn replacement project.
The UC Master Gardeners are part of the University of California Cooperative Extension system, serving our community in a variety of ways, including 4-H, farm advisers, and nutrition and physical activity programs.