Raised bed from 2.4m 'sleepers'

[Radian]

I'm planning to make some raised beds for growing veggies and the current thinking is to make 1.2m x 2.4m frames by cutting one 2.4m x 0.2m x0.1m tanalised 'sleeper' in half to make the ends, with two more sleepers for the sides and stack two frames to create a 0.4m high bed out of six sleepers.

 

The first question on my mind is would the 2.4m sides 'give' too much when filled with soil? I could use chunkier 0.25 x 0.125 sleepers but they're £45 each rather than £30

 

Seems like such an obvious design, I wondered if anyone else here had already built something similar?

[Gone West]

3 hours ago, Radian said:

Seems like such an obvious design, I wondered if anyone else here had already built something similar?

Not yet, but was going to later this year. I was going to use the 100mm thick sleepers and if they did flex tie them together on the inside with a short post half way along. Keep us updated I'll watch with interest.

Edited May 4, 2023 by Gone West

[saveasteading]

I used 4  x 4 timber packers from steel deliveries. Lapped them and screwed them together downwards and ends, and it is working fine after 4 years.

 

I didn't bother with corner or side pegs.

 

There is negligible load from the soil. 

If you practice 'no dig' the soil will stabilise permanently too. It becomes a crusty entity, crisscrossed by wormholes and good fungi.

 

I don't fancy cutting the sleepers though, unless of course they are sitting there foc. I fear they might also distort dramatically when cut.

 

Start collecting cardboard (without sticky tape) and newspapers to lay on the ground. They smother the grass and weeds, then rot away.

 

The amount of worms in mine is amazing, due to compost and manure on the top over the winter.

[Radian]

1 hour ago, Gone West said:

Not yet, but was going to later this year. I was going to use the 100mm thick sleepers and if they did flex tie them together on the inside with a short post half way along. Keep us updated I'll watch with interest.

 

Just a tip about using a halfway post - if they're just driven into the ground it won't do much. The trick is to tie across from the other side with galvanised steel strap between the posts. This goes under tension and holds the sides in. I'm beginning to conclude that there won't be too much flex without extra retention anyway so probably not needed.

 

1 hour ago, saveasteading said:

I used 4  x 4 timber packers from steel deliveries. Lapped them and screwed them together downwards and ends, and it is working fine after 4 years.

 

 

Interesting, that's something I hadn't considered - I could use standard 0.1m square fence posts. I like the idea of being able to screw down each layer to the one below. I've modelled that as well as the jumbo sleepers (which I'm ruling out now):

 

 

Annoyingly, the price of using two 0.1m square posts is generally more than that of a single 0.2m x 0.1m sleeper.

I hoped the volume sales of fence posts would help here but evidently not. It's pissing me off that all these timber products are more than twice the price they were the last time I did any hard landscaping🙄

[joe90]

I recently built a raised bed for my nephew but only one full sized railway sleeper high on its side. Joined the sleepers with angle iron and coach bolts in the corners and straight brackets on the straight join in the middle, worked well.

[Radian]

2 hours ago, joe90 said:

I recently built a raised bed for my nephew but only one full sized railway sleeper high on its side. Joined the sleepers with angle iron and coach bolts in the corners and straight brackets on the straight join in the middle, worked well.

 

Sounds good and chunky. I like the idea of using angle iron. If you can hand-pick railway sleepers to get decent ones you can't really beat them but if at the mercy of what gets delivered then I've seen plenty that I wouldn't want to grow food in!

I'm thinking of using these 300mm x 32mm angles on the inside to hold it all together while gunning Waterproof No More Nails onto the mating surfaces.

and of course plenty of:

 

 

[Gone West]

13 hours ago, Radian said:

Just a tip about using a halfway post - if they're just driven into the ground it won't do much. The trick is to tie across from the other side with galvanised steel strap between the posts. This goes under tension and holds the sides in. I'm beginning to conclude that there won't be too much flex without extra retention anyway so probably not needed.

Originally I was going to use dung boards, because they come in 4.8m and 6.1m lengths, and have several short posts along the lengths to stop flex. Wendy didn't think they were chunky enough so the plans changed to sleepers. The idea was for two 3m long raised beds seperated by a 1m walkway covered by a long arch, so forming a cross shape. The problem is long chunky bits of oak are a lot more expensive than dung boards.

[Alan Ambrose]

>>> Seems like such an obvious design, I wondered if anyone else here had already built something similar?

 

Yeah, I built a bunch for our garden. Some 1 sleeper high, some 2, some 3. I got the supplier to cut them which made things easier. To reduce rot, I lined the sides with DPC and stapled it in and just screwed big screws through the ends to hold them together. For long thin beds I also used threaded rod between the sides to stop them bowing apart. I'll put up some photos. I'll probably use the same method again on our new build when the time comes.

[saveasteading]

For rot I only painted them with creosote substitute (looks like old sump oil).

All good after 4+ ? years except some big fungus growing...which i reckon is a sign of the health of the soil.

 

Mine are simply frames, sunk 50mm into the ground. No anchors, braces, pegs or cross bars.

 

I would not line the inside with plastic as it will make it damper.

 

I made a small trowel hole to plant a lettuce, and disturbed about 5 worms.. The worms are doing a great job. 

I am utterly converted to "no dig" gardening.

 

Mine are not, however, handsome features, just doing the job.

[saveasteading]

Here are mine.

[Radian]

3 hours ago, saveasteading said:

Mine are not, however, handsome features, just doing the job.

Look good to me! Not sure where you have them as upper left looks like it might be an asphalt drive? Mine are going at the front of the house in a forgotten corner to the side of the drive.

Does everyone just plonk them down directly on the soil or put in gravel or some other barrier to slow the rot?

[saveasteading]

Number 1, I just took out the turf and laid them in there.

Next time I had learnt not to bother, and I  took out the turf only enough to set the timber down beneath it, and put cardboard over the rest.

 

It  needed to be set down, to resist the spread of roots. If it wasn't in grass, i don't think it needs recessing at all.

 

Note the VPL as a weed suppressor.

[DarrenP]

I used full width oak sleepers on ours, I bedded the bottom ones on their sides then did the top laid flat like a T I doweled the top to the bottom along with screws from inside upward so they were hidden

 

 

[Radian]

1 hour ago, DarrenP said:

I used full width oak sleepers on ours

They look great. Did you oil them? I priced-up Oak and the extra expense didn't strike me as being a show-stopper but I noticed that a 2.4m sleeper weighed in at 50Kg and decided against it!

Cutting and machining are all much more difficult and I understand that you need to use stainless-steel screws otherwise the resins eat them. Apart from that they look beautiful and last a lot longer.

[DarrenP]

1 hour ago, Radian said:

They look great. Did you oil them? I priced-up Oak and the extra expense didn't strike me as being a show-stopper but I noticed that a 2.4m sleeper weighed in at 50Kg and decided against it!

Cutting and machining are all much more difficult and I understand that you need to use stainless-steel screws otherwise the resins eat them. Apart from that they look beautiful and last a lot longer.

Yes I used Osmo UV oil as we are south facing. The oak cost me around £35 I think so wasn't too bad and yes hard work to cut... I used a belt sander on the top as its a good seating area so didn't want any splinters  

[IanR]

I created a 10m x 4m veg patch with 2 rows of untreated oak sleepers (3m x 200 x 100), side on. Filled with earth that regularly gets rotovated, and no sign of movement after +5 years.

 

 

 

 

 

[saveasteading]

1 hour ago, IanR said:

 Filled with earth that regularly gets rotovated,

Now that it is established, I really recommend " no dig". It's not just a gimmick or lazy, it works really well.

National Trust veg garden nearby say that since theirs got established they never water after 2 weeks in the ground. I'm trying that this year.

[Sparrowhawk]

2 hours ago, saveasteading said:

Now that it is established, I really recommend " no dig". It's not just a gimmick or lazy, it works really well.

This but you have to keep on top of the weeding. I didn't this year and now having to "dig" to get the big weeds out, disturbing the worms and lovely soil 😒

[saveasteading]

15 minutes ago, Sparrowhawk said:

have to keep on top of the weeding.

I made the mistake of spreading unrotted manure. Horses guts don't appear to digest seeds.   But easy to hoe the seedlings. I should have put a membrane over it.

As you say, keep on top of it. Less work overall.

[IanR]

7 hours ago, saveasteading said:

Now that it is established, I really recommend " no dig". It's not just a gimmick or lazy, it works really well.

 

I'm a traditionalist. My veg plots get turned over twice a year with the winter turn including lots of compost etc. The one in the picture less so, but the other I have started was quite heavy soil and I've still got some way to go get it in good condition. Even then though, I'll still be turning them over every year. 

[saveasteading]

34 minutes ago, IanR said:

I'll still be turning them over every year. 

Up to you of course. Some people like the digging.

 

I don't, but my compost is great and just gets spread on the top, and the worms do the rest.

It also means that plants can be in small areas, all year.

 

As i understand the science of it, the undisturbed worm holes allow a more active biodiversity underground, and especially of microbes and fungi, that are a benefit.

Digging breaks all that up.

 

I've got very heavy clay, which is like brick in the summer. I might sometime dig an experimental hole in a raised bed to see what has changed, if anything , below the soil line.

Soil mechanics meets gardening...keeping it relevant for BH.

 

[IanR]

27 minutes ago, saveasteading said:

Digging breaks all that up

 

Not really. There's lot's of different approaches and each has its positives and negatives. You just need to pick what works for you and your soil.

[Radian]

12 hours ago, IanR said:

I created a 10m x 4m veg patch with 2 rows of untreated oak sleepers (3m x 200 x 100), side on. Filled with earth that regularly gets rotovated, and no sign of movement after +5 years.

 

It looks like you bedded the sleepers down onto concrete pads where they connect - did you just dig a pit for the concrete at those points and level-fill to get an even base?

[IanR]

Just now, Radian said:

It looks like you bedded the sleepers down onto concrete pads where they connect - did you just dig a pit for the concrete at those points and level-fill to get an even base?

 

That Looks deceiving. What you can see is the over-site from the build. There's no concrete under the sleepers. The long edge closest to camera is just sitting on the over-site. The back edge of the veg patch had to be dug in a little to get it level as the garden slopes down a little towards the bottom of the photo. On the lower course of sleepers along the long side I did drill a few Ø10 holes vertically, and then hammered in some Ø8 rebar through the sleepers and into the ground. 

[Radian]

12 hours ago, IanR said:

There's no concrete under the sleepers

 

Fooled me there 😄 I'm having a bit of a head scratch about what to do next. Here's the site with 8 sticks marking the corner positions of the beds:

 

 

I was going to spread gravel around the beds but I have around 100 x 450mm concrete slabs lifted from our old patio and stacked behind the garage. They could be laid as a flat area and the sleepers placed on top (with the slabs removed from under the beds):

 

 

But I don't really want to make it the full-on patio build that I'd normally do (excavate 200mm, whaked-in 150mm MOT type 1, 20mm mortar bed, 30mm slab etc.).

I'm wondering if loose-laying on a screeded bed of sharp sand might be sufficient? Drainage would be a bit better overall such that I might get away with laying it without a fall (it would seem wrong to have a fall on the beds anyway).

I still need to dig down to undisturbed soil (clay probably) and the whole area slopes down towards the wall and into the corner where the fence meets the stone wall and I can't really build-up with excavated soil in the corner as it will settle in time.

That'd mean having a 250mm deep sandpit in places 🙄