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The wife and I just spent 30 minutes creating an edge for our lawn. We've done one side so far. We used a lawn edge knife and edge shears.

grass lawn edge

I often see people with crisp edges for their lawns, how do they do it? Do they buy these things? Or is it just a matter of constantly cutting back growth around the edge?

I have done this before, but the grass just grew back and it now looks like this:

growth around edge

How do we go about maintaining the grass edge crisp and clean?

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There is no one "right way" to create and maintain a crisp lawn edge.

When I was much younger than I am now, I did exactly what you are doing, except I used a flat spade to cut the edge and a trowel to clean it up. I did do one thing differently: I removed all grass cut from the edge from the garden, after knocking the soil off - it tends to root into the garden if you don't do that.

I would do this every spring for over 30 linear meters of garden. And then I got older and this became too much work. I also had a neighbor fall into the trench I'd created; she nearly sprained her ankle.

If you don't want to do this trenching annually, then you have to look at some kind of edging product. Note that I'm in the US, so the products I mention may not be available in the UK.

Bricks

Pros:

  • Permanent installation.
  • If placed vertically, their depth really keeps the grass roots from growing under the bricks and into the garden.
  • Easy to maintain the edge because your lawnmower wheels can ride on top of the bricks, not the soil.
  • Could be relatively inexpensive, depending on your source. If you haunt a building demolition project, you might even get them for free.
  • The trench you've already made will make installation pretty easy - just dig it a bit deeper and give it a flat bottom. Level the height with sand and place the bricks.

Cons:

  • Can move both vertically and, especially, horizontally due to frost heaving
  • If placed horizontally (especially wide side up), then grass roots will grow underneath the bricks, making them ineffective at maintaining a neat edge
  • Grass roots will take advantage of the gaps between the bricks and enter the garden.

Bullet-nose Pavers

Pros:

  • Permanent installation and unlikely to move via frost-heaving.
  • Taller pavers act like vertical bricks to keep grass roots out of the garden.
  • Easy to maintain the edge because your lawnmower wheels can ride on top of the pavers.
  • The trench you've already made will make installation pretty easy - like with bricks, just give it a flat bottom. Level the height with sand and place the pavers.
  • The interlocking nature of the pavers makes it easier and neater to make curves.

Cons:

  • Grass roots will take advantage of the gaps between the bricks and enter the garden, although the interlock will make this more difficult for the roots.
  • Roots trying to get between the pavers will make the top look untidy (grass will grow between the pavers). You must therefore weed your edge occasionally to keep the edge clean.
  • Not all bullet-nose pavers are equal. In the US, some large stores sell pavers that are only 5-7cm high. This is too shallow to prevent roots of most lawn grasses from growing under them.

Metal Edging

Really the gold-standard for edging products.

Pros:

  • These products give a beautiful, professional edge.
  • Permanent installation and, if installed properly, unlikely to move due to frost heave.
  • Depth is usually at least about 9.5cm (4in), so able to keep nearly all grass roots out of the garden.
  • The trench you've already made will make installation easy. If it's not 9.5cm already, deepen it, then place the edgers and stake.

Cons:

  • The edging is by far the most expensive product you can use.

  • The metal panels usually contain holders for the stakes that are punched from the panel rather than braised on as a separate piece. This allows grass roots to easily infiltrate through the edging and into the garden. You should use a small piece of aluminium flashing on the lawn-side of the panel to prevent this. No dealer tells you this, by the way.

  • Because these are staked vertically, you can sink the edging below the level of the lawn if/when you step on the edging while working in the garden (especially in spring or after a rain). This require you to either periodically lower the edge of the lawn or raise the edging if you want to maintain the clean line.

Plastic Edging

By far the most common edging in the US, due to cost. The best edging is purchased in the US as 20 ft straight "sticks", although most consumers go for the flimsy (and crappy) coiled edging sold in boxes.

Pros:

  • Cheap - maybe only $2/linear foot (not sure what the price in the UK is)
  • If rolled edge (the large plastic cylinder at the top), staking is done horizontally and if properly installed, the edging will never frost-heave. If straight-edged staking is vertically so there is a minor possibility of frost-heave
  • if you know how to properly join two pieces of edging, there is no gap between two "sticks" of edging
  • The height is comparable to metal edging, so it does a great job keeping grass out of the garden.
  • For rolled-edge plastic, there are no openings in the edging for staking.

Cons:

  • Edging purchased coiled in boxes has a "memory" and will never allow you to create a straight line without kinking. Even creating nice looking curves can be difficult.
  • If rolled-edge plastic, then the edge created may not be as crisp as you'd like.
  • If straight-edged plastic, then there typically are openings for stakes which lead to grass infiltration.

Recycled Plastic

I have no direct experience with this product, but it resembles metal edging or straight-edged plastic edging in looks. I suspect that it is installed very much like metal edging, with vertical staking. Keeping it gap-free between sections may be an issue, although some systems I've seen use recycled-plastic pieces that slip onto each edge of the adjacent panels to connect them. If vertically staked, frost-heave and sinking-due-to-stepping may be issues as they are with metal edging.

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  • That is a great answer, thank you 🙏 will these work good? diy.com/departments/red-block-kerb-l-200mm-w-100mm-t-125mm/…
    – J86
    Feb 24 at 15:56
  • @Jurp Metal edging does not do well with grade changes as I found to my dismay on a project. :(
    – kevinskio
    Feb 24 at 21:32
  • 1
    @kevinsky - That's an excellent point! I remember a firm I worked for had to try to install 20 ft lengths of aluminum on a grade with a dip in it. They had to cut it something like 8 times and then join the lengths to try to piece it together and cover the dip (we couldn't fill in the dip, unfortunately). The client didn't want plastic or pavers. It was a nightmare. I assume that the same issues would arise with the recycled plastic, given it's in rigid lengths like the metal edging.
    – Jurp
    Feb 25 at 0:17
  • Yes, I think the pavers you've linked to will work. It appears that they may be slanted on one face? If so, you might want to install the slanted face towards the garden rather than the lawn. Note that the pros and cons for brick pavers would apply to these pavers.
    – Jurp
    Feb 25 at 0:23
  • The big problem with edging products (at least the ones commonly available in the UK) is that you if the edging is lower than the grass level the grass will overhang and it is hard to trim the edge neatly, and if they are higher they will either break or damage your mower, depending on the quality (the cheap plastic stuff is almost guaranteed to break!)
    – alephzero
    Feb 25 at 1:59
2

A few comments:

You need a half moon edger such as this one here and long handled shears like here.

Your border soil looks a bit lumpy and weedy. Maintaining a decent edge is a lot easier if the adjacent soil is a reasonably fine tilth - ideally it should look like it's just been poured out of a bag of premium topsoil :-) If it was me, I'd regularly spot treat those weeds and grass growing in the border with Roundup. Then I'd break up the clods with a fork or hand cultivator and then rake the soil so it uniformly slopes from the bottom of the lawn edge into the border.

You don't need to use the half moon edger very frequently (maybe every couple of months or so depending how fanatical you are). However, when you do use it, you must take your time. Work slowly and precisely to make the edge both well defined and with the line of the edge a beautiful smooth curve.

Trim the lawn edges with the trimmer every time you cut the grass.

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  • That is the exact edge knife that I have. The bulldog one, that is what I used. :) I’ll do weeding tomorrow, you’re right about that.
    – J86
    Feb 24 at 17:21
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You can use whatever you like for edging round the lawn, from bricks to a plastic lawn edge, but the grass will still grow over the top. For a sharp edge ongoing, use the lawn edger in spring (sometimes necessary again in autumn if it butts up against paving) and then just use the long handled lawn edging shears (where the blades are sideways on) whenever you mow the lawn. You don't need a deep trench at the edge either, it only needs to be an inch or so. The worst bit is actually picking up the 'leavings', the bits you've cut off...

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  • 1
    Hi Bamboo. I'm surprised to read you only go down an inch in your trench.; Sincere questions: how do you keep the grass roots from quickly growing into the garden? And what mulch do you use? I used to use a 4" deep trench for mulch and enough exposure to allow for air-pruning of grass roots. I always like hearing how other gardeners handle the same situations that I've run into. :)
    – Jurp
    Feb 25 at 14:34
  • Inch or so with a slope away from the edge - I hate that wide trench look at the edge of a lawn, its dead ugly. I don't have any trouble because I redo the edges with lawn edging shears every time the lawn is mown, so it doesn't get a chance to grow into the beds and borders. In fact, I quite often just do the edges for a quick tidy up if I haven't time to mow, or it hasn't grown very much and the weather is hot and dry. Keeping the edges crisp and tidy makes it look good even if the lawn is a bit long. But perhaps your lawn grass is not the same as ours here. No mulch in the trench.
    – Bamboo
    Feb 25 at 22:05
  • @Bamboo-Most lawn grass in the northern US is Kentucky Bluegrass (sun) &/or perennial ryegrass and fescues (esp in shade). Bluegrass is a horrible weed in a garden. When I trenched, I planted dianthus and other low growers (esp annuals like sweet alyssum) at the top of the trench - they would grow down into it, softening the lines. I'd also get a few volunteers-one year, I had Lobelia cardinalis seed in from a mother plant 60 feet away. A weird place for it, but it was beautiful when it bloomed. I remember Stormy, who posted on this stack that she (?) trenched 6in deep & 8in wide. Incredible.
    – Jurp
    Feb 25 at 22:20
  • Our lawns here are comprised of similar grasses with the exception of Bluegrass, so perhaps less problematic. Lucky with the Lobelia cardinalis - I love that plant, but it doesn't overwinter here most years - most likely the combination of wet and cold rather than just low temperatures. No need for mulch with a small trench at the lawn edge here either since the lawn roots are not exposed, and we have a maritime temperate climate anyway.
    – Bamboo
    Feb 26 at 1:09

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