Borders: how do I stop lawn grass from encroaching into garden space - Ask Extension
How deep, and what materials, do I need to stop grass from tunneling under or "jumping" over a border and wreaking havoc in a garden of vegetables or ...
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Borders: how do I stop lawn grass from encroaching into garden space #256478
Asked June 23, 2015, 2:13 PM EDT
How deep, and what materials, do I need to stop grass from tunneling under or "jumping" over a border and wreaking havoc in a garden of vegetables or flowers? Grass seems to have no appreciation for where to stop, and will cross a 4-inch ditch with a 4-inch plastic running border buried up to its rounded top on the far end. Are there "plates" or other objects you recommend that will keep grass in its place? And how deep do I need to bury them to stop a grass root invasion?
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Montgomery County Maryland
Expert Response
Grass is actually one of the most aggressive plants in the world. And, there are many species of grass--not all are equally aggressive.
It will grow through any crack, of course, where pavers or bricks or mowing strips are installed.
Normal lawn grasses do not grow under barriers usually (although grassy weeds such as Bermudagrass and Quackgrass will) So a depth of 1-2" should suffice for most turf grass.
The biggest problem is usually that it grows over the barrier. Grass will send out side shoots or rhizomes that create a mat and can slowly encroach across a 1 foot paver easily. However, it takes time. Annual or semi-annual attention would be needed to re-edge the pavers. And simply tearing off the mats isn't very difficult.
A cut edge ditch must be recut yearly in order to keep roots from crossing the ditch. The ditch is bare soil. Nature hates a vacuum. So, eventually it will fill with vegetation of one sort or another. The lawn side of the ditch is cut straight down to shear the roots. The other (bed) side is at an angle.
The plastic rolls of border are normally very effectively for many years, and may be the least labor intensive barrier, once it is installed. The trick is to mow all the way up to the border and be sure the soil levels stay the same on both sides of the plastic. If soil gets higher than the plastic on the either side, the grass roots can reach over it.
Also, grasses seed themselves. So, they can easily jump 4" and reseed, especially weed grasses.
Sorry, no silver bullet here. Vigilance will be required, but a little attention can stop big infestations.
ECN
It will grow through any crack, of course, where pavers or bricks or mowing strips are installed.
Normal lawn grasses do not grow under barriers usually (although grassy weeds such as Bermudagrass and Quackgrass will) So a depth of 1-2" should suffice for most turf grass.
The biggest problem is usually that it grows over the barrier. Grass will send out side shoots or rhizomes that create a mat and can slowly encroach across a 1 foot paver easily. However, it takes time. Annual or semi-annual attention would be needed to re-edge the pavers. And simply tearing off the mats isn't very difficult.
A cut edge ditch must be recut yearly in order to keep roots from crossing the ditch. The ditch is bare soil. Nature hates a vacuum. So, eventually it will fill with vegetation of one sort or another. The lawn side of the ditch is cut straight down to shear the roots. The other (bed) side is at an angle.
The plastic rolls of border are normally very effectively for many years, and may be the least labor intensive barrier, once it is installed. The trick is to mow all the way up to the border and be sure the soil levels stay the same on both sides of the plastic. If soil gets higher than the plastic on the either side, the grass roots can reach over it.
Also, grasses seed themselves. So, they can easily jump 4" and reseed, especially weed grasses.
Sorry, no silver bullet here. Vigilance will be required, but a little attention can stop big infestations.
ECN
