The heading pretty much sums it up.
I've got a raised-bed garden built from two courses of 2x12" planks, supported by wooden posts set in concrete. The bed is bordered on two sides by a bermuda grass lawn. The grass is constantly invading the bed (see the pictures), and is very difficult to get rid of. How can I keep it out?
I've thought about buying a grass barrier and burying it along the edge of the raised bed so it extends just an inch or so above the soil surface on the lawn side. But I've read that bermuda grass rhizomes will grow two or even three feet down to get under a barrier, and the barriers I've found are only ten inches wide.
I've also thought about digging a trench along the edge of the bed and pouring a concrete barrier. But I don't think I have the brawn to dig a two foot deep trench around the two sides of the bed (at least 60 feet), and I don't see how I could use a trenching tool without removing the bed's walls completely, so all the dirt would spill out. And I'm really not up for lugging, mixing, and pouring the amount of concrete I'd need.
If you have relevant experience and you can tell me how your plan works out in practice, what do you suggest?
