When planning your raised bed garden, one of your first decisions will be what you will do about ground cover. It’s important to consider a ground cover if you have any sort of rhizomatous, running or invasive plants where you plan to locate the garden. Some examples of these would be bermuda grass or bindweed. By "groundcover", I mean a barrier to prevent grasses and weeds growing in the pathways of your garden.
On our farm, our main concern is bermuda grass. If left to grow freely around raised beds, it will infiltrate them and take over, so it’s important to smother it in paths as well as beds. In this post, I will walk you through what we ultimately decided on for our garden and other options for ground cover.
Here’s what we did for our garden...
First, we rolled out two strips of 15 ft wide Dewitt Sunbelt woven landscape fabric over the entire garden area and stapled it with landscape pins. It’s really important to pick a product comparable to Dewitt Sunbelt, as weaker fabrics will not work.
Note: 4 ft wide is a more common and more accessible size. If doing a simpler or smaller layout I would probably try using 4 ft wide fabric in a grid, leaving the ground under the beds exposed, and keep it simple by leaving all paths 4ft or 8ft wide throughout the garden.
Next, we assembled our beds and put them in place according to our desired layout. Once the beds were in place, we marked the fabric where they should be in case they got bumped out of position.
Before filling each bed, we used a razor knife to cut out the majority of landscape fabric from inside the bed, leaving a few inches so it didn’t slip out.
Having ground contact was very important to us so worms, roots, moisture and soil life can function and travel freely.
After the garden was built, we kept the black plastic exposed for an entire season. Some folks decide to leave it exposed permanently, and I was tempted to. Some drawbacks to that:
- It gets so hot in summer I can’t walk barefoot in the garden.
- It’s ugly.
- Weeds will still grow on the landscape fabric even if you don’t intentionally cover it. Soil will fall and blow in, collecting around the edges of the beds, weeds will root through the fabric if they germinate on top of it.
- You can’t use a flame weeder.
- Although it is UV treated, it won’t last forever if left exposed to the sun, especially in our extreme Texas summer. Covering it up will greatly prolong its lifespan.
We considered a number of different materials to cover the plastic with. Ultimately, we decided decided to go with cedar mulch, and we’re stoked about how it turned out:
- Pros: Affordable and lightweight. Very easy to move with a 5 tine manure fork and wheelbarrows. I scattered it by hand evenly throughout the garden. It smells great.
- Cons: Will eventually break down into soil and weeds will grow in it. Weeds will need to be cultivated, pulled or torched.
We also considered rock such as decomposed granite or crushed limestone.
- Pros: Hard for weeds to grow in it, looks great.
- Cons: Expensive and heavy. Some don’t like decomposed granite as it can stain.
Living groundcover is another option. If you don’t have any aggressive grasses or can establish something peaceful in their place, living pathways seem like they could be the best option.
If you have time, you could tarp the entire area for 6-12 months to kill all vegetation, then sow your living groundcover into it immediately upon uncovering.
One improvement to our garden would be to install an edging of some kind around the perimeter of the fabric so there would be a barrier to grasses creeping in from the sides and we would have a solid edge to run a string trimmer. For now, I carefully string trim the edge and also have to pull weeds by hand from time to time.
Let us know about your garden groundcover experience in the comments!