HOW TO KILL
SODCUTTER : Rent a sodcutter. This machine cuts the roots two to three inches deep and disconnects the grass from the soil beneath. The “rugs” of grass must then be flipped over so that the roots can be exposed to the sun and it will die. Does not work well with Bermuda grass since Bermuda grass roots go so deep and the stolons - the tiny bits of root left in the soil when you rip it out - can resprout and become new full-grown plants. The “rugs” of sod that you flip over are left on the ground as a mulch, protecting the ground beneath from getting baked by the sun. The dead sod can be moved aside whenever you need to dig and plant Pros : can kill a lawn in a day, especially bluegrass or St. Augustine Grass, leaving you with essentially a blank canvas Cons : labor intensive, sodcutter is heavy as shit.
SOLARIZATION/SMOTHERING : Cover lawn with a tarp or cardboard and mulch (need lots of mulch, like a dumptruck full). Easiest in lower-latitude hot climates like Texas. May not be possible in Eastern, higher-rainfall climates like Maryland, the Carolinas, Pennsylvania, etc.
This method takes a while, which is a drag, and I’ve seen it fail. The time that it takes to die could be time that you’re spending getting native plants established. Thus I recommend the sod-cutter or just doing the bit-by-bit method.
BIT-BY-BIT : Using a “Sharp-shooter”shovel (basically a long, narrow, 3-times-longer-than-it-is-wide shovel), you come at a low angle (mimicking the flat-slab subduction of the farallon plate, for any of you geology nerds), disemboweling the turf from ground in a back-and-forth stabbing motion. This doesn’t look as nice as using a sod-cutter to rip out uniform even lines of turf, but it works. It sucks to do and is exhausting, but you only have to do it once. Then you plant your natives, dump the mulch on top of the ground (while keeping it two inches away from the stems of natives so as not to encourage rot) to smother weeds and help retain soil moisture, water them in, and you’re done.
TILLING : Only possible with grass species that do not spread by stolons, like bermuda does. Bermuda grass is extremely hard to kill and often requires constant weeding or site-specific spraying and selective, targeted applications of herbicide using a large piece of cardboard to prevent over-spraying or hitting native plants. Tilling essentially “chops up” and plows the lawn into the ground beneath. With species like Kentucky bluegrass, it works like a charm. With Bermuda, it is pointless.
EASIEST, LAZIEST (andthat’s ok) METHOD : JUST START PLANTING STUFF, WHILE CONTINUING TO WEED-WACK AND MOW THE LAWN AROUND THE STUFF YOU PLANT.
The key take-away no matter what is that after you kill the lawn, you will essentially be planting and nurturing the natives, while continuing to go in and periodically remove or weed-wack/spray/dig-up-with-a-garden-knife any remaining bits of grass that pop up. I highly suggest against using herbicide unless you have one of the very invasive and aggressive grass species like Bermuda or Kikuyu Grass. St. Augustine Grass, by comparison, is easy to remove and kill.
The process of constant maintenance works because the native shrubs you initially plant (which should be easy to grow, common keystone members of your local ecosytem) will eventually outcrowd and overgrow the invasive grasses, and you will be the disturbance force that selects for the natives and selects against the attempted re-intrusion of the grasses. After a long growing season where you have watered the natives, any competition will successfully be put at bay since the natives have taken most of the available light and root space. Once you have reached this point, very little continued maintenance is necessary, especially for prairie gardens since prairies tend to be so dense.
Happy to spread the gospel 🙏 I'm surprised it wasn't already posted here!