Stabilising slopes with wooden pallets

PALLETS OF PLENTY: Using timber pallets in steep-slope gardening provides ledges to help plants established their roots and stabilise the soil. Photos: Hannah Moloney.
PALLETS OF PLENTY: Using timber pallets in steep-slope gardening provides ledges to help plants established their roots and stabilise the soil. Photos: Hannah Moloney.

There are a great many techniques for stablising steep slopes in your garden, and one of the many ways we've used recycled materials to keep our slope from sliding down the hill is by using timber pallets.

We salvage these for free from the side of the road, building sites and warehouses.

They're treated with heat, so are chemical free - this means they'll break down sooner rather than later, but before they do, you can use them in countless ways.

If you're searching for some yourself, look out for the HT stamp on the pallet.

When identifying what type of pallet you're looking at, 1001 Pallets recommend looking for two main things:

- The IPPC Logo: if you don't see it, don't use it! Even if a pallet may be perfectly safe without this logo, it could also mean that it was treated with chemicals.

- The treatment code: [HT] = Heat treatment; [DB] = Debarked; [KD] = Kiln Dried - these are safe to use. [MB] = Methyl Bromide (toxic, avoid use).

Heat treated (HT) pallets are "built to break", meaning they'll start to break down within fiveish years as they're not treated with any chemicals to preserve them.

They undergo a pest control treatment called heat treating (HT) which involves heating the pallet to a minimum core temperature of 56°C for softwoods and 60°C for hardwoods for a minimum of 30 minutes in a kiln.

Check the labels on your pallet, you want to see the IPPC logo and 'HT' meaning it's heat treated and without chemicals.

Check the labels on your pallet, you want to see the IPPC logo and 'HT' meaning it's heat treated and without chemicals.

A word of caution: If you notice liquids spilt onto the pallet, don't use it as it could be a harmful substance you really don't want near your vegie patch.

If there's no stamp on the pallet we say leave it. While it might be fine, the risk of contaminating your soil is not worth it. Better to be safe than sorry and considering there's approximately a "gazillion" pallets out there, you can afford to be picky.

The first time we tried the wooden-pallet technique was for a super hot and dry slope, and we were unsure which plants would really thrive in such a compromising position (without heaps of pampering).

Because of this, we initially planted a range of herbaceous, edible and native plants to "test" which would work. The winner (by far) was creeping boobialla (myoporum parvifolium).

We're big fans of this vigorous native ground cover and have planted it in some of the hardest spots in our garden where not much else survives (except invasive grasses).

Using pallets to help stabilise soil - a game changer for steep-slope gardening.

Using pallets to help stabilise soil - a game changer for steep-slope gardening.

One of these plants will happily cover up to two-three square metres densely which is absolute gold when you live on steep slopes.

Creeping boobialla puts down roots along the length of its "branches", so while we planted each plant at the top of the bank it put down roots from top to bottom.

At the top of the bank the creeping boobialla meets a solid planting of garden thyme, an edible herb that is also a ground cover - we love the way they merge into one another seamlessly.

Creeping boobialla completely covers pallets beneath to help stabilise a steep bank.

Creeping boobialla completely covers pallets beneath to help stabilise a steep bank.

Using pallets to help stabilise our soil has been a real game changer for us in steep-slope gardening. The pallets provide lots of ledges to plant into, making it easier for plants to get established.

It's also easier to irrigate and passively harvest rain, as water is slowed down (a little bit), instead of quickly rushing down each bank.

So in solidarity with all of you slope dwellers out there (it's hard work, hey) we offer up yet another approach to working with steep, steep slopes to foster landscapes which are accessible, productive and beautiful.

All power to you!

  • Hannah Moloney and Anton Vikstrom are the founders of Good Life Permaculture, a landscape design and education enterprise regenerating land and lifestyles.