Is it a good idea to build your raised beds from railway sleepers? Let’s jump into the pros and cons of using railway sleepers for your raised beds and see whether this is the method for you!
Reclaimed Railway Sleepers
Straight off the bat, I will say do not use reclaimed railway sleepers for raised beds. Yes, they will last forever, but they are not suitable for use near anything you plan to eat. Let me explain.
The treatments railway sleepers go through to make them suitable for use on railways for many years are pretty intense.
These are hardcore industrial processes that involve some nasty chemicals. Chemicals that you will not want anywhere near the stuff you plan to eat.
I am not sure about the exact modern process, but arsenic was a popular ingredient in old preservatives and will be present in many reclaimed sleepers in some form.
Now you don’t want this touching your soil where it could leech into it.
Your plants will then absorb this, and who knows what could happen, but I know I don’t want to put lots of effort into growing my veg only to have it contaminated by some nasty chemicals!
Some say that the nasties won’t leech out of the railway sleepers, but I remain firmly unconvinced. Why even take the risk in the first place?
New Railway Sleepers
These, on the other hand, are a different kettle of fish and safe to use. The treatment methods now used for pressure-treated timber are much safer after they stopped using creosote.
You can use modern treated timber for your raised beds, and as such new sleepers will be fine.
How long do tanalised sleepers last?
If you have just built something out of tanalised sleepers, then you no doubt want to know how long your marvellous creation will last. Well, let’s have a look and find out.
Tanalised sleepers are likely to last between 10-15 years. This can change depending on what conditions they are placed in. Usually, the wetter they are, the quicker they rot.
If your wood is submerged in water, it may last as little as 3 or 4 years. So it is important to keep the sleepers as dry as possible. You do not want them to be in any sitting water at all.
Softwood or Hardwood
Traditional railway sleepers are hardwood, usually oak, but many of the new sleepers sold as railway sleepers these days are often pressure-treated softwood, so which should you use?
Softwood sleepers will be cheaper, easier to manoeuvre and easier to work with than their hardwood brothers. On the other hand, hardwood sleepers look better and last longer than softwood sleepers.
Softwood sleepers will last around 10-15 years in soil without added protection. Whereas with hardwood sleepers, you are looking at more like 30-40 years of life.
How To Fix Sleepers to the Ground
You have a few different options here. Let’s go through the more popular choices and discuss pros and cons.
So this is your first choice, do absolutely nothing. Sleepers are big heavy pieces of timber. Often you don’t need to do anything to stop them from moving.
Particularly if the posts are laid widthways, you don’t need to fasten them to the ground unless they are used for a retaining wall.
Laying a gravel/sand mix under the sleeper is always a good way to help drainage. The sleeper will not be quicker if the base is always in wet soil.
You can use a post, either in front of or behind the sleepers to attach the sleepers to. You set these posts into the ground like you would with a fence post. So dig a hole and set the post in concrete or postcrete.
Rather than a massive post and concrete, you can also hammer a smaller stake into the ground. You can then screw the sleepers to this stake.
This is essentially the same idea as the posts just without the need to dig big holes and concrete posts into the ground.
Tons of specialist metal anchors are available for fixing sleepers to the ground. These are mainly for smaller builds, think single raised beds or edging.
You hammer the anchor into the ground and then simply screw the sleepers to the bracket at the top. Nice and easy. A really simple method but doesn’t provide the same level of stability as using the large wooden posts.