I have raised beds that are deep!
Deep beds are areas of soil that have been double dug and are not stood on. They are not necessarily marked out.
Raised beds are surrounded by wood, brick or other material to lift the surface of the soil above the surrounding paths, they are also not stood on.
I dug all my plot including the path areas and when enough was dug to place a bed into position, the frame was laid on the soil and its 'footprint' marked out. A shallow trench about 3 inches deep was created all round the marked area and the frame dropped in. It was levelled and corner posts hammered in.
The dug soil from the surrounding paths was transferred into the bed, ant the effect was to leave the soil surface 6 inches above the paths. The soil in the beds was now deeper than it was at the start. The process was repeated 29 times.
I used timber decking from B&Q which was 2.4m long. The timber is good quality and the close grain means that coach screws will get a secure grip..
I cut a length into two for the ends and this means that three are used for each bed. At about £5 each board, the total cost including corner posts and coach screws is about £17.50.
I bought a lot in 2006 when they were on offer and using my old gits discount card got them for £3.50 each, about £12 a bed.
It may seem extravagant but it can be done bit by bit and of course any old timber can be used if you are not worried about the look.
My system means that I have half sized frames that sit on top of the beds and can be moved anywhere on the plot to:-
Raise the sides to protect against wind.
Protect from birds by attaching netting.
Create a frame by attaching polythene.
Protect from frost or carrot fly etc by attaching fleece.
Drill a hole as shown to avoid splitting and extend it about 2cm into the end of the adjoining board.
70mm bolts are about £12 a hundred from B&Q and £3 a hundred from Screwfix Direct. I have used a thousand,
building beds, frames and compost bins.
The photo of the plot shows the beauty of having all the beds the same size. Various "modules" can be moved about the plot. There are 3 hinged high frames that were used to grow butternut squashes last year. There are overwintered broad beans, peas, ans salad stuff in them at present.
Some units are just rectangles of squares to give height and others are covered in polythene, netting or net curtain for use as different crops require.
There are netted units that are used to protect brassicas from pigeons and butterflies.
The first 15 beds have corner pots as described above, but the last 15 at the bottom of the plot have no postas I realised that they were not necessary as the weight of the soil keeps them in place.
I have nearly completed the paving of the paths with 400mm slabs from B&Q. 260 slabs bought a few at a time have cost about £300 which is lest than the cost of a carpet.