Raised Beds...

[steveal]

My wife would like a raised bed to grow vegetables. The spot for the raised bed is on very poor land, so the beds need to be about 18" - 24" high for a decent depth of good, new soil.

I thought to use a couple of 8' x 4' sheets, cut in half lengthways to make a bed about 8' long x 4' wide.

The question: What sort of sheet material would be suitable?

Plywood? OSB?

Any insights much appreciated.

Steve

 

[Roger]

You don't need any floor to the beds - just a good solid surround of whatever material you decide, such as brick, stone or wood (Sleeper type).

Putting down wood underneath is bad for any plants, the soil beneath and the soil in the beds themselves. Just dig over as much of the base soil as you can, weed it thoroughly. build the surrounds, fill them in and plant.

 

[Jorden]

Hi Steve

I agree with Roger, the soil you are going to hold in the beds (if my arithmetic is ok) weighs about 3 tons, so sheet material probably wouldn't hold it for long. Best bet is to go with railway sleepers, they look good too


Dennis

 

[Roger]

Reading this again Steve - Oops! I thought you were talking about making a floor Go for the Sleepers though.

 

[wizer]

on my allotment I have used 8x2's

OSB or any man made board is no suitible for plant beds. As said above, your best bet is clean sleepers. Or you could use 2 8x2's on top of each other, giving you 16 inches.

 

[Paul.J]

Hello Steve.
I've done what Wizers done but used 8"x2" tanalised.Been down for about 6 years now and still solid
Paul.J.

 

[ByronBlack]

Hi Steve

I'm in the process of making a vegetable patch for the missus, it's about 18'x3'x2'. I've dug out the area, racked and forked the soil ready to receive a compost/loam/manure mix.

The 'boxes' of 6'x3' will be lined with breeze block, the outside will be rendered, no floor.

I would agree with everyone else here, do not use sheet material, use either masonry/brick or tanalised timbers, and it's worth preparing the soil ready to receive the proper stuff, by this I mean remove the bulk of the large stones, rake and fork etc.. this will stop any deformaties as the veg grow down in to the soil.

 

[Scrums]

If you can beg/ scrounge/ steal..........I didn't say that, did I ? Scaffold boards - they're good too.

Chris.

 

[steveal]

I didn't describe my plans very well...
I'm not using the 8' x 4' as a bottom.
Sliced in half, lengthways they make 4 sides, as follows:
2 at 8' x 2' and
2 at 4' x 2'
That makes the perimeter sides for a bed 8' x 4'.

I want the 2' depth because the "soil" on which it sits is actually rubble. I think 8" deep just isn't enough, maybe 16" would be OK.

The reason for choosing 8' x 4' sheets was low cost and ease of making.

Steve

 

[ByronBlack]

Steve, I think your better of with a masonry option as it'll hold the soil excellently and will be very cheap compared to sleepers.

 

[Bodrighy]

If you can beg/ scrounge/ steal..........I didn't say that, did I ? Scaffold boards - they're good too.

Chris.

If you do this make sure you don't have loads of cement on them, a lot of plants don't like cement round there feet.

If you have to put some kind of flooring down you're beter off putting down some knd of tarp and sticking the fork through it to allow for drainage.

Pete

 

[dickm]

There's aparently some worry about using railway sleepers for raised beds, because of the tar in them.
Not saying this matters - round here, the cost of sleepers is so high that you could have an organic box delivered for several years for the price of the timber, so it's purely theoretical.

 

[Losos]

Steve,

Even cutting up some 8x4 sheets to make the sides is a non starter IMO

As everyone has said, and I can confirm, ply. OSB, MDF will all suffer greatly outside. Water is their main enemy. Within six months you'll have warped, bending, crumbling, sides to your beds annd SWMBO will not be best pleased DAMHIKT

Railway sleepers are ideal (Right size & weather protected) Scaffolding boards might be OK (I've never tried them so can't say for sure) If you can get pressure treated 4x2 you could stack three on top of one another to give you 12 inches. Unless you're aiming for champion size carrots etc. I would have thought 12 inches would be deep enough.

 

[bobscarle]

I shall be taking up the deck in our back garden soon. My dad has already requested the boards to make raised beds on the allotment. Always something to be scrounged!

Bob

 

[wizer]

again, man made board material just wont last. What about 8x2 and 4x2? I think 10 inches is your minimum if you dont have any soil underneath them

 

[mahking51]

Hi all,
I use tannalised half round posts for my two large raised beds; hammer in lengths as uprights (24") and nail long legths to them. I also lined with black bin bags to keep the gaps weed free.
Been down 5 years now no problems
Looks nice and rustic.
Regards
Martin

 

[Anonymous]

I've just spent the evening trawling though allotment forums to find out whether I can use tanalised timber to repair the raised beds on my newly aquired allotments.

Then I find that the answer was here all the time!

Down to B&Q tomorrow to buy a generator so I can run my tools on the plot!

Virgil

 

[Keith Smith]

Up until relatively recently tanalised timber used to contain arsenic and chromium which leaches out into the soil. The latest tanalising, Tanalith E is supposed to be a lot safer (based on copper and triazole) only time will tell, but tanalised timber is classed as hazardous waste in many countries!

We have just taken up all our tanalised boards out of the veg plot and replaced them with oak sleepers. £22 + VAT each so not so cheap, but the whole point of growing my own veg is to try to avoid a lot of the chemicals they liberally apply to get the perfect looking specimens people seem to want to eat :?

Keith

 

[ByronBlack]

Virgil. You can get brown eco-friendly tanalised timbers now. Please take a look at the website linked in my signature where my girlfriend has notes and pictures on three raised planters that I made for her using this timber.