Raised Veg bed

[ash_scotland88]

Looking for some guidance for building a raised bed.

Thinking of using old scaffold boards and building an 8ftx4ft by 3planks high. So 9 planks in total.
For corners thinking of using fence posts and just screwing in. I'd like it if the screws where from inside to outside but don't think it would be secure enough to do that. The only other detail is staggering the corner overlap, if that makes sense?

Do I need to line it? Is there any major flaws in my plan?

 

[GSXRMovistar]

Are you planning on using scaffold boards as you already have them available? Otherwise just consider using 200mm x 100mm sleepers and timberlok type screws to secure them together (no need for corner posts).

 

[sovietspybob]

I used pallet collars to build 2, this is the first and i did another with an extra layer. Used some batoning i had lying around to screw them together and chucked some spare wood stain on them. Don't know if it was the right thing to do but i lined them with clear plastic after painting to keep the moisture from the soil away from the wood to try and give them a but of a longer life.

Not the best looking thing but a very cheap way to do it.

 

[PlacidCasual]

I would suggest 4 foot is too wide you will have difficulty accessing the centre without damaging the plants near the outside, plus the separation between rows will eat into your space. If you can get extra boards and have the space two 8 by 2 or 8 by 3 beds might be more convenient and productive. My first polytunnel had wide beds and they were a real pain, my second had narrower beds and much easier to actually access so you did a much better job.

edit: I agree lining the sides it is a good idea it will slow down the wood rot and help keep the moisture in the bed. Make sure you put lots of manure vegetable matter in the bottom of the bed to store water and provide long release nutrients.

 

[ash_scotland88]

Cheers.
8x4 is accessible on both long lengths and one short length. Would this still be an issue?

Scaffolding planks as they are fairly cheap. The sleepers are more expensive, but saying that not priced up fence posts but don't see those making up the difference.

 

[Amp34]

I used 6x2 untreated timber to make mine, with 4x4 posts for the corners. It will rot, but it’s that cheap that if I need to replace them in 3–5 years so be it. I didn’t line the boxes, but it’s a lot drier here so waterlogging isn’t as big an issue.

Using treated wood is controversial, some suggest the preservatives will leak into the soil and be absorbed into the veg, but realistically there’s little chance of any issue, especially if you’re not going to garden fully organically. I went with untreated as I’m going as organic as possible.

An alternative option is to see if you can find some Cedar planks. They’ll be expensive but are extremely resistant to rot so have the benefits of treated timber, without any of the chemical preservatives

I recommend you make yourself a large sieve (3ftx3ft using small holed metal wire and timber) and sieving the soil into the the boxes. It’ll take some time but you’ll have stone free soil which will help with carrots and other root veg. I added a bale of peat/organic material into each 8x4 and then a few bags of manure. Aim to add more compost/manure each year.


8x4 is fine if you can access both long sides.

 

[ash_scotland88]

Yeah, need to find a way to sieve soil. We have a large pile from removing it to build the base for the shed and I know it's full of stuff.

 

[Baboonanza]

I recently build beds with scaffold board and just overlapped the corners and used 3-4 inch long wood screws to hold it together. The boards are thick enough and 3 of those in each will hold it easily, plus you can always add some additional metal brackets for reinforcement if you're worried.

 

[Mercenary Keyboard Warrior]

Yeah, need to find a way to sieve soil. We have a large pile from removing it to build the base for the shed and I know it's full of stuff.

Thats easy https://www.screwfix.com/search?search=riddle

If you do filter all the stones etc out, make sure you mix in some organic material, well sieved soil compacts a lot and can starve the roots a bit as it doesn't allow water to pass as well.

Don't make them wider than twice your arm length. I have a bed I inherited at our allotment, probably 8 foot square its a pain to even water the middle.

Any reason to make them so high?
The higher they are the less water they retain and the deeper the plants have to go to find some moisture.

Lining is a thing, its tricky but not impossible (use damp proof sheet), but you still end up with stuff going behind them into the gap over time. Does mean you can use anything to help preserve them though.

The chemicals leeching thing goes back to when they were based on copper and stuff like that, now they are pretty much inert.

 

[Amp34]

Good luck using a hand sieve/riddle for a load of raised beds!

You need to do that at the very least, and that will still take quite a fair amount of work (took us a couple of weeks on and off to do our three beds, with the pile of soil directly next to the beds).

If you have a lot of soil then a rotary soil sieve system may be a better bet.

 

[Mercenary Keyboard Warrior]

The thing when using a riddle or similar is to use the correct grade to start and work down, the issue is they get blocked so you start large and pass them a few times through lower grades.
People try to do it as a 1 pass and they get blocked easily or they use wet soil etc which means you need to start even bigger

I wouldn't overly filter it was well, smaller stones help with drainage.

Our allotments are on ex farming land, was carrot fields, and the size of the flints that come out every so often, doesn't affect the ability to grow anything.
In fact the soil being less compacted (which can be an issue with really destoned soil) means root crops grow to an uber size with no impact as they just compress whats around them

About the only time I really worry is when i am making a peat&soil seed bed, then I filter the soil down to a very fine tilth

 

[t-rex]

Cheers.
8x4 is accessible on both long lengths and one short length. Would this still be an issue?

Scaffolding planks as they are fairly cheap. The sleepers are more expensive, but saying that not priced up fence posts but don't see those making up the difference.

Sleepers aren't too bad if you can get them at a good price. I made a 12' x 4' x 40cm high raised bed using sleepers from these guys:
https://www.pennyhilltimber.co.uk/categories/products/landscape-sleepers/green-landscape-sleepers
You'd be looking at 4 x £15 for the 8 foot sleepers and 4 x £8 for the 4 foot sleepers.

I fixed together with these:
https://www.screwfix.com/p/timbascrew-flange-timber-screws-silver-6-7-x-200mm-50-pack/8498j
which I set inside ~inch wide holes, about 5cm deep, and covered with hardwood dowel sawn flush to the sleepers (width of hole = width of dowel).

You'd be looking at just over £100, probably double the cheaper scaffold board option, but I wouldn't hesitate to say it'd be worth the extra spend.

 

[Kutter]

i did these for the last 3 years, way easier and only cost is 4 stakes and string.

 

[Amp34]

The thing when using a riddle or similar is to use the correct grade to start and work down, the issue is they get blocked so you start large and pass them a few times through lower grades.
People try to do it as a 1 pass and they get blocked easily or they use wet soil etc which means you need to start even bigger

I wouldn't overly filter it was well, smaller stones help with drainage.

Our allotments are on ex farming land, was carrot fields, and the size of the flints that come out every so often, doesn't affect the ability to grow anything.
In fact the soil being less compacted (which can be an issue with really destoned soil) means root crops grow to an uber size with no impact as they just compress whats around them

About the only time I really worry is when i am making a peat&soil seed bed, then I filter the soil down to a very fine tilth

I agree with pretty much everything you say, any home made riddle should be around half to 3/4 of an inch in coarseness to allow for some material to fall through, but clearing out the majority of the rubble from your average garden soil is beneficial.

Doing it by hand with a small 18” riddle will take forever though! There’s a reason the angled system is used regularly.

 

[Mercenary Keyboard Warrior]

I agree with pretty much everything you say, any home made riddle should be around half to 3/4 of an inch in coarseness to allow for some material to fall through, but clearing out the majority of the rubble from your average garden soil is beneficial.

Doing it by hand with a small 18” riddle will take forever though! There’s a reason the angled system is used regularly.

Yeah thats exactly what I thought.
I was struggling at my allotment last year as i said doing some fine stuff and one of the old boys said to me the mud wasn't right so I would struggle.
He said dig over this patch I was trying to do and make sure it was well broken up and come back in a week as long as it didn't rain a lot, I did and it basically fell straight through.
Mud dint look any different to me to be honest but it went through about 20 times easier than when I was first trying.

I am sure i will make the same mistake this year. May just ask him when to do it

But if you havent got a clue then I guess a brute force method will work for most of us