Front and center in the news and in your garden is the drought and what you can do about it in your own landscape. If you’ve dabbled before with replacing thirsty plants with climate-appropriate low water use California native plants or those from areas similar to ours this is the year to step up your efforts.
Gov. Brown’s mandate for water conservation state wide is a call to action to transform our landscapes into resilient gardens that not only save water but act to build the earth into a living sponge that harnesses rainwater and replenishes the aquifer.
Replacing that water guzzling lawn now that the kids have grown or dramatically reducing it’s size is a good place to start and is easier than you think. If you’ve been paralyzed with the thought of digging out and hauling away hundreds of square feet of heavy sod or using dangerous grass-killing chemicals, sheet mulching is the method for you.
This simple technique eliminates the lawn by smothering it with layers of recycled, compost and renewable materials. Here’s how to do it:
1. Mow the lawn down to 1-2”, leave the clippings in place and soak with a hose. Don’t worry. This soaking is nothing compared to what you’ll soon be saving by removing your lawn.
2. Flag the locations of sprinkler heads you will be keeping for your new plantings and cap off the ones you won’t need.
3. Add an inch of compost to speed up the decay of the grass. If your lawn borders a driveway, path or sidewalk you’ll have to remove about 3” inches deep of soil along these edges and back 8-12” so that the new mulch doesn’t slide off into the sidewalk.
4. Put down 2-3 layers of newspaper or one layer of cardboard overlapping the edges by 6-8” to prevent regrowth at the edges. You can buy recycled cardboard in rolls for larger projects or find your own at appliance or bicycle stores. Wet the cardboard or newspapers to keep them in place as you go along. It’s best to use cardboard or newspaper that will break down quicker. Weed fabric is not recommended as it takes much longer to break down. Don’t use plastic sheeting because water and air cannot penetrate it.
5. Add a 3” layer of mulch such as bark chips from a tree trimming company. You can use compost, straw or shredded plant material. If you have Bermuda grass or other weeds like oxalis you will need to layer about 8”of mulch to smother them.
6. Water thoroughly.
If you can wait a month or more to let the decomposition process get going so much the better. If you just can’t wait you can begin planting now by scraping away the mulch and poking a hole in the cardboard or newspaper where the plant is to go. Then add some compost to help the new plant become established. Be sure to plant high enough to prevent crown rot and keep the mulch a couple inches away from the stem. The top of the root ball should be 1-2” above the soil and just below the mulch.
Modify the sprinkler to drip and remember to adjust your irrigation system run times to accommodate your new plantings.
This is a basic “lasagna” method for lawn removal. If you are planning to replant with water smart grasses you would choose finer composted mulch instead of bark chips. Either way the process works on the same concept as a compost pile. As the lawn dies from lack of light, it decomposes with the activity of beneficial worms, insects and microorganisms coming up from the soil and doing their job to break down the nitrogen and carbon in the sheet-mulch layers. It’s a win-win situation for the environment and your water bill.