After the 2013-2017 drought in California, many people recommended replacing lawns with native plants.
Outdoor water use accounts for more than 30 percent of total household water use, on average, but can be as much as 60 percent of total household water use in arid regions in the summer. Source EPA
Native plants use 85% less water than turf.

  1. Mow or weed whack the weeds that are protruding up too high.
    Water or wait for rain.
  2. Cover with overlaping cardboard boxes flattened or 6 layers of newspaper.
    Make sure any seams or holes in the cardboard are covered. Some grasses and other plants are very persistent and with the slightest bit of light they reach up a tendril to survive.
    Don't use wax coated or glossy cardboard; you want it to decompose.

    Don't use landscape cloth because it had tiny pores to let water thru and it will allow light to come thru allowing weed tendrils to survive and penitrate thru.

  3. Water cardboard so it is somewhat soft and therefore malleable and easier to keep down.
  4. Cover with 3 inches of humus.
    Some sites say to just use 4-6 inches of mulch.
  5. Cover humus with 3 inches of mulch.
    Some sights recommend straw.
  6. Wait 6 - 8 weeks for the grass to be completely dead.
    The cardboard will partially biodegrade in 6 months and be easy to punch thru.
    Plant seedlings in the humus.
    Regular watering softens the cardboard and by the time the plants have grown to almost full size the roots can easily penetrate deeper through the cardboard into the soil underneath.
The compost layer is sometimes placed above the weed barrier. There are no definitive scientific studies on the effectiveness of the order of layers when used on different lawn types or in various climates. The recommendations in this Garden Note are based on local success with brown-in winter and patchy lawns.

One site recommended digging a trench around the lawn because The grass along the edge is the hardest to kill, as water seeps in from the concrete and pools there. Digging out the grass prevents runners from re-emerging and growing onto the sidewalk.

Note I couldn't find Redi-Grow Humus anywhere. ACE had another kind.
Earthgro Organic Humus and Manure Walmart 5

What Is Humus Made Of - Learn The Difference Between Compost And Humus

Sterilize your Lawn - Solarization (Heat Treatment):
Soil solarization is an environmentally friendly method of using the sun's power to control pests such as bacteria, insects, and weeds in the soil.
"Sterilization can improve soil structure by increasing the availability of nitrogen and other essential nutrients" according to UC IPM (Integrated Pest Management.
A study published in Pedobiologia showed that "Seedlings grown in sterilized soils produced higher root biomass"

Temperatures routinely used to heat soil will not result in completely sterile soil / potting media. The goal is to heat the potting mix to a point that kills the plant pathogens of concern.

The lawn is covered airtight with plastic .
The plastic sheets allow the sun's radiant energy to be trapped in the soil, heating the top 12 to 18 inches. When properly done, the top 6 inches of the soil will heat up to as high as 150°F, depending on the location.

It should be done as spring is turning to summer when temperatures are above 80o.
Water the soil deeply (1 foot). Steam is needed to kill nematodes, weed seeds, and insect eggs in the soil and damp soil conducts heats faster. To maximize the benefit of solarization in sandy soils, lay drip irrigation lines under the clear plastic cover and add water regularly.
Wetting will also cause some seeds to germinate and then be killed by the heat.
Cover the area with clear plastic (such as 1 to 4 mil painter's plastic).
(Some sites say to use black plastic, but most call for clear.)
Bury the plastic edges in the soil to trap the heat.
Leave in place for about 4-8 weeks--depending on how hot the weather is--until grass is dead. (Don't leave it down longer than 8 weeks, or soil structure may suffer.)

Target temperatures needed to kill specific organisms for moist soil or potting medium heated to the target for a minimum of 30 minutes:
Moist soil, 30 minutes at Organisms killed
120F (49C) watermolds (oomycetes)
145F (63C) most plant pathogenic fungi, bacteria, and viruses, worms, slugs, centipedes
160F (71C) plant pathogenic bacteria, soil insects
180F (82C) weed seeds
212F (100C) heat resistant plant viruses and weed seeds

Source: Baker, K.F., 1957.

Other recommended time / temperature treatments

  • Maintain 140F (60 Celsius) for 30 min to pasturize nursery soil if using aerated steam Greisbach et al 2012.
  • Maintain temperatures of 158°\;F or higher for 30 minutes, or 140*F or higher for one hour, to kill most pests in soil in containers through solarization UC IPM publication 74145.
Soil Solarization - Texas A&M
Soil solarization - Sunset Magazine
Heat treatment of soil for plant propagation |
Soil Solarization for Gardens & Landscapes Management Guidelines--UC IPM

How to Kill Your Lawn |
Grass Removal Methods - UC Master Gardener Program of Sonoma County
Smother and Replace Your Lawn With Mulch
An Easy Way to Start a New Permaculture Garden
ANR - Beyond Lawn - Sacramento Master Gardners
ANR - Lawn Removal: Do It Right - The Real Dirt Blog
PlantNative - How To - Site Preparation
Weed Control Without Chemicals: Best Organic Methods
Fall is the time to replace lawns and gardens with water-wise plants | UC Davis
How to Kill a Lawn to Replant With Drought-Resistant Plants | Home Guides | SF Gate
What Is Humus Made Of - Learn The Difference Between Compost And Humus

last updated 10 Oct 2018