How To Keep a Lawn and Garden Beds Separate

Maintaining a clear boundary between your lawn and garden beds is a smart way to keep your landscape looking tidy. It also stops grass from creeping into your flower or vegetable beds. Read how to create a physical barrier between the two and maintain the separation in our step-by-step guide below, and watch the video above for tips from This Old House landscape contractor Roger Cook.

Understanding the Problem With Lawns and Gardens Mixing

Grass has a natural tendency to spread, and can encroach on garden beds. This invasion can sap nutrients and water from your garden plants, increase the time you need to devote to lawn upkeep, and make your outdoor space look messy.  You can create a physical barrier between your lawn and garden beds to address this challenge. A barrier defines the space visually and helps prevent grass from spreading to unwanted areas.

Tools and Materials to Separate Lawns and Garden Beds

You’ll need the tools and materials below to properly form a barrier between your lawn and garden beds:

• Chemical-resistant gloves
• Half-moon edger
• Hammer
• Herbicides
• Safety goggles
• Steel edging
• Square shovel
• Wheelbarrow

Creating a Physical Barrier Between Your Lawn and Garden Beds

One effective way to keep your lawn separate from your garden is to install a physical barrier. A barrier requires only three installation steps: edging the bed, digging a trench, and installing steel edging. It’s also very easy to maintain.

Edging the Bed

Begin your project by edging the bed with a half-moon edger. Follow the steps below. 

1. Use a half-moon edger to cut a straight line along the edge of your garden bed.
2. Drive the edger deep into the soil and lift to create a clean cut. Sever grass roots to stop regrowth.
3. Be careful not to flick grass and soil into the bed. Sweep or collect it instead.
4. Continue along the entire edge. Keep a consistent line for a well-defined boundary.

This method creates a clean, functional edge that looks great.

Digging a Trench

After you’re done edging, dig a trench that will act as an air barrier between the lawn and bed. Use a square shovel to dig along the new edge. Remove the grass and soil and dispose of it or use it elsewhere. The trench should be deep enough to create a gap that prevents grass rhizomes from spreading into the garden.

Installing Steel Edging Between Your Lawn and Garden Beds

Consider steel edging for a more permanent solution that requires little upkeep. Follow the directions below.

1. Place the steel edging into the trench.
2. Use steel stakes to secure the edging. Pound them flush with the top so that they’re stable.
3. Overlap the ends of the edging sections and secure them with stakes to create a seamless look.

Steel edging costs more upfront, but it’s durable, low-maintenance, and leads to long-term separation.

Dealing with Existing Grass in Garden Beds

You might find grass growing in your garden bed even after you install a barrier. Address this issue promptly to maintain the overall health and appearance of your garden.

Using Herbicides

Herbicides can help you deal with stubborn grass. Follow the steps below.

1. Choose a non-selective herbicide such as glyphosate that targets grass.
2. Apply the herbicide carefully to avoid harming desirable plants.
3. Use a foam brush to apply the herbicide for precision and minimal waste.

Herbicide blocks an enzyme that grass needs to grow. It kills the grass within 24 hours, though visible results may take a few days.

Manual Removal

If you prefer a chemical-free approach to keeping your lawn and garden bed separate, consider removing grass manually. Just pull the grass by hand, and make sure to grip the roots to prevent regrowth. Use a garden fork to loosen the soil around clumps of grass for easier removal. Repeat the process regularly to exhaust the grass’s energy reserves.

Manual removal requires more effort but is a natural way to keep grass under control.

Maintaining the Separation

Once you’ve established a clean boundary, set up a maintenance routine. Consider the tips below. 

• Check periodically for any grass that crosses the barrier and remove it early.
• Reapply herbicide to keep grass from getting out of hand.
• Use a string trimmer vertically along the edge to maintain a clean line.

Staying on top of maintenance will save you time and effort and keep your landscape neat and tidy.