How to Use Treated Pine for Garden Edging

Are you thinking about using treated pine for your garden edging project?

Treated pine is less expensive than hardwood because it grows faster and can be easily cut into boards and planks of various shapes and sizes.

The difference in cost means that treated pine is more affordable for DIY projects.

Is treated pine good for garden edging?

Treated pine is generally a good option for garden edging. They provide a strong border for your garden, which looks great and helps keep everything in its place.

As long you choose the right level of treatment, your timber will be resistant to rot from exposure to moisture and will also be termite resistant.

What type of treated pine should you use for garden edging?

Garden edging | How-To Guides

The next step is choosing a treated pine that will suit your requirements.

Treated pine is given a hazard rating based on the level of treatment it has undergone.

The ratings are H1, H2, H3, H4, H5, and H6. The higher the hazard rating, the more durable it is against moisture and insects.

For garden edging where the wood will be in contact with soil and water for prolonged periods of time, choose timber with a hazard rating of H4 or above (H4 timber is the best option).

H3-rated timber is not designed to be in contact with soil, making it unsuitable for garden edging.

You should also avoid using H2 or H1 rated timber outdoors because these are only meant to be used indoors as they aren’t able to withstand exposure to water.

Is it safe to use treated wood for vegetable gardens?

Many people prefer not to use CCA treated pine (which contains arsenic) for vegetable gardens. However, CSIRO does assign a tolerable risk, based on their research.

ACQ treated timber is generally considered to be safer to use than CCA as it does not contain arsenic.

However, as discussed in this report by Pennsylvania State University “ACQ contains more copper than CCA, and some copper will leach from ACQ-treated lumber as it does from CCA-treated lumber.”

If you are concerned, you can line your vegetable garden with plastic or another material to prevent leaching.

You could also use untreated hardwood sleepers as an alternative to treated pine.

Keep in mind that root vegetables such as carrots, potatoes, and beetroots are more at risk of absorbing toxins from the soil than above-ground growing fruit and vegetables.

How to Use Treated Pine for Edging

Here are the basic steps for installing your treated pine garden edging:

  1. Measure up your garden and determine what size pieces of timber you need.
  2. Cut your timber or order it pre-cut from your local supplier.
  3. Use a shovel to dig a channel around the edge of your garden. Keep in mind that the channel should be more narrow than your timber.
  4. Insert your timber into the channel and use a mallet to bang them into place. Check they are level.
  5. You can use wooden stakes as appropriate to keep the treated timber upright.
  6. Use nails to secure your timber in place. You can also use timber glue if you would prefer to not have visible nails or screws.
  7. Once you have secured your edging in place, fill any gaps between it and your lawn with wood chips or mulch for a natural effect. Alternatively, you can fill the gap with soil if you want the garden right up to the edge.
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Steve Kropp

Based in Melbourne, Steve's passion is vegetable gardening, and he’s been writing about it for almost 5 years. He also loves all things DIY and is always looking for a new project. When not working on his own garden projects or blogging, Steve enjoys spending time with his family, cooking meals with produce harvested from his garden, and coaching his son’s footy team.


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