Last weekend I pulled out the tomato plants (all but three) and did the yearly Bermuda grass removal. Bermuda grass is one of the two most frustrating parts of my vegetable garden, the other being the deer. Bermuda grass (Cynodon dactylon) grows and spreads through rhizomes (under the soil) and stolons (above the soil). Any piece of the roots or stolons left behind will regrow which makes removing Bermuda grass very difficult.
To remove the Bermuda grass I use a trimmer and cut back all the grass to the ground. Then I till up the soil multiple times. After each run with the tiller I rake up the roots and stolons for collection and dump them. The remains never go in the compost bin as all it takes is one little piece of uncomposted Bermuda grass to wreak havoc later. I repeat the process until as much of the grass is out as possible. It will come back, but this process makes a major dent in it. The disadvantage of this method is that the tiller cuts the Bermuda grass into smaller pieces which can resprout. In the spring before planting I’ll need to repeat the process and then again in the fall. This probably will not eliminate it but should keep it under control. Every piece of Bermuda grass root that is removed will mean a smaller problem later.
Another method for removing Bermuda grass involves completely removing the soil. To do that you need to remove at least 6 inches of soil to be sure all the roots are accounted for. That is a lot of soil to remove so I prefer to use the tilling method to leave the majority of the soil in place.
A third method to remove Bermuda grass is to smother it. Multiple layers of cardboard covered with a good 6 inches of mulch then left in place undisturbed for several weeks to even months. For me this isn’t a good option since I would then need to leave the area unplanted for too long.
Solarizing is another method. A plastic sheet can cover the area which increases the heat underneath and reduces moisture in the soil which will eventually kill off Bermuda grass. Solarizing Bermuda grass can take several weeks to accomplish.
The best strategy is probably a combination of all the above methods. Unfortunately seeds from Bermuda grass can cause another round, as can a small sprig of grass mowed in from the lawn or dropped by a nest building bird. Keep your garden well mulched where you can and be as aggressive as the Bermuda grass in your fight!