We are slowly trying to become self sufficient at our property and have a piece of land that has poor access for the mower etc and is covered in rough grass, so I have decided to put in a raised bed and grow root vegetables (potatoes, kumara etc). See before and after pics
The raised beds seem to be much more successful for growing and I have already built several (photos are included in this I'ble) but this is the first one that I have properly documented.
The basic construction is the same for all the ones I have done, just small details/shapes/sizes etc have changed
The whole thing is made from 6x2 H4 timber (or 150x50 if you are metric) and I used 6m lengths to minimize the cutting
These can be made with no nails allowing them to be deconstructed if required, I am going to use a few nails as these are going to be in for good and make the whole thing more stable.
EDIT For all those commenting that H4/ pressure treated lumber is toxic, please read the text
1. The whole thing is lined with plastic to prevent any chance of chemical transfer
2. Arsenic is no longer used in pressure treatment (and hasn't been for many years)
3. Studies have shown that toxic transfer is a MYTH!!
4. I didn't build out of cedar as it is eye wateringly expensive in NZ
EDIT2 if you really want to know the dangers (or lack thereof of using Pressure Treated Timber in raised bed go HERE www.naturalhandyman.com/iip/infxtra/infptforraisedgardens.html
Step 1: The Wood
I ordered a dozen 6m lengths of 6x2 rough sawn H4 timber (H4 means that it is treated for in ground use, mine are above ground but it means they wont rot any time soon)
I got this on sale at NZD $3;60 per metre + tax (so about $4 a metre) so $288
I decided that as there was space I would go for the easy dimension of 6m x 3m, so I cut a couple of the lengths in half with my compound mitre saw
Step 2: Layout
So I laid the wood out in the area I am going to build, just to get an idea of the dimensions.
It is also a lot easier to build in situ rather than build elsewhere and dismantle/reassemble
As yuo can see the grass in this area is pretty rough ( I will dig this out later) also the area isn't flat so I will do some jiggery pokery when building.
I took the opportunity at this point to move all the wood over (as I was feeling strong)
Step 3: Notching the Timbers
So for a "No Nails" construction there has to be some way of joining the wood., you could try the powers of positve thinking, but it is much more reliable to notch the timbers.
I marked out the position 100mm from the end amd then set my circular saw to a depth 1/4 of the timber width (ie 1.5 inches or 38mm) In reality set it a fraction more than 1/4 to ensure sufficient depth ( I went for 40mm)
I then made several parallel cuts and removed the waste wit a chisel, on completion the bottom of the notch was cleaned out by sideways movement of the circular saw (you can use a chisel but power tools are quicker!)
Step 4: Rinse/Repeat
So carry on and notch the other side the same way and both sides of the other end, repeat on all the other pieces
As you can see I checked the notch width with a piece of scrap 6x2
You may find it easier after the first couple of pieces to partially assemble the next laye and transfer measurements upwards for accuracy of assembly
Step 5: Start Assembling
Now you can either cut all the pieces and then assemble or as I do cut them as you are going as sometimes there needs to be a bit of adjustment and it's better to do it as you go along.
As you can see the area is a bit slopey so I will level it on bricks and take care of that when I fill it
Step 6: Carry on Going!
the top "short ends need a piece of 6x2 cut in half lengthways but the same principle applies
Step 7: And That Would Be It
To all purpose at this point it is complete, ready for filling etc but a few finishing touches make it more practical
Step 8: Nice Extras
It is always nice to have somewhere to sit at the edge of a bed when weeding, planting etc, so a piece of 6x2 on its side makes a convenient perch.
This was the only place I used nails in the whole build, to secure this on the top.
The corners all have half lap joints to make it all a bit neater, again just cut out by making 1" deep cuts with the circular saw and cleaning out with a chisel
Step 9: Finished and Ready for Filling
I will line the inside walls with plastic (old feed bags) to minimise the chance of rot, however being H4 it shouldn't rot in any case.
Then will have to fill it, I estimate it will take 9 cubic meters of soil -- another day I think, at least I have a big pile of top soil close by!
The whole construction took a little under 4 hours to build, could have been a lot quicker with a helper to lift some of the bits (and if I didnt keep putting tools down and forgetting where)
Check out my other I'bles for different takes on raised beds--- I have built a few now!! There is also one pictured above which is a slightly more complex design - but same principles apply (this one is 6m x 6m)
Once filled I use weedmat and macademia nut shells as a mulch as we are on tanl water and thus want to keep watering to a minimum
This mulch along with the plastic lining mean that even at the height of summer we only have to water once a week
Also when filling I do alternate layers of the sandy soil we have, then topsoil (3 inch deep layers) topped off with about 4-6 inches of good quality compost or manure ( I get Alpaca poo by the truckload from a neighbouring Alpaca farmer--(don't know where he gets it from though!! :-) )