hello all, had such an epic day yesterday up at the soul patch but was going to see if anyone had any canny and most importantly cheap ideas of how to create large raised beds. i am thinking 2 20ftx10ft beds so quite a lot of material needed. any thoughts well appreciated!
That configuration negates the most important aspect of typical raised beds, being able to reach every part without climbing in... if you have to climb up into your structure it isn't really a raised bed now is it... you then may as well make one 20' X 20' bed and use less materials.
I'd make them sized so that you can reach in to the entire area without climbing in and so that they use common dimensional building materials. Don't think too much about low cost at the expense of quality... the cheap always comes out expensive... there is no point to building something if it will collapse even before the first season. Something important to consider is to build your raised beds so that it bars small tunneling critters, otherwise it's all for nothing... they will come. Large critters are easy to deter, the small critters require special efforts.
I used real RR ties (used) but I lined the entire interior with aluminum flashing that extends a good ten inches below the baseline surface, it keeps tunneling critters out plus prevents leaching from treated lumber... also helps tie all the RR ties together especially the corners. It was easy to add the flashing later when I discovered the small critters coming to my salad bar. I built my bed one RR tie high, (~12"), works for me. Mine isn't a typical raised bed, it's a raised vegetable garden that I go into... the border serves to prevent my good amended soil from washing away from heavy rains plus makes it much easier to keep critters, both large and small, out... also deters weeds from creeping in, and it was easy to attach a deer fence to the ties, you may not need such. Mine is 50' X 50', you probably don't want something so large but the same construction would work for any size.
Till the ground to the same depth that the raised bed will be above the natural level. That is, if the raised bed will be 1 foot high, till to a depth of 1 ft. While tilling, add bone meal or superphosphate; phosphorus does not readily dissolve and so must be placed where roots will find it. Also add some organic matter (e.g.: peat moss, compost) but not much; until you frame the bed, you do not want to raise the soil level significantly.
Choose framing materials (e.g.: old railroad crossties, concrete (cinder) blocks, 2x12 boards). Your choice should balance cost versus how long you plan to maintain the bed. Also, your choice might depend on whether or not you are planning "organic" gardening since some framing materials are chemically treated to resist rot.
Frame the bed. For a bed 20x10, you will want to anchor the framing material even if you frame with something heavy such as a single course of concrete blocks. I would not use wooden stakes. Instead, consider scrap water pipes or steel rebar. You should use lengths at least twice as long as the frame will be high. Pound the anchors into the ground so that the top of each is about 1 inch below the top of the frame; this is to reduce the risk of tripping on the anchor.
When the bed is framed, pile enough soild amendment inside the frame to about 2-3 inches higher than the frame. Till this into the top half of what you already tilled. Mixed with your native soil, this will quickly settle down to the level of the frame.
Plant.
No, I have not recommended specific framing materials or soil amendments. I do not know what is available in your area or -- for what is available -- what the costs are.
Why on earth would you make them 10ft wide? They should be no wider than you can reach into the centre without standing on the bed, usually 3 to 4 ft. This will have a longer perimeter for the same area and so cost more than 10ft wide but you don't want to walk or have to push a barrow over your bed.
New materials like concrete blocks or timber that is durable in contact with the soil tends to be expensive. If you can get such second-hand you may save much.
Corrugated iron (eg colorbond) is cheaper and works well but has the disadvantage that you cannot sit on it. You will still need to put an edging strip along the top all the same for safety.
How high do they have to be? If only short maybe no sides are required. Where will you get the soil to fill them?
David
I would like to try this, as I'm tired of the Mickey Mouse job I did of raised beds.
But I don't understand how sloped sides can maintain their shape. Doesn't rain, or even watering, break down those sloped sides?
TIA
HB
For sides with about a 30 degree slope and height of 30cm (1 ft) there is very little movement due to watering. If you go steeper or higher the problem gets worse.
D
Yeah, ain't gravity a bitch! LOL
With a 30º slope and one foot high why bother, may as well just garden on the flat ground. With that configuration and nothing to contain the earth everytime one cultivates/rakes or otherwise works the soil within one season it'll lose at least half it's height... it'll need constant reforming leaving little time for plantings to acclimate, not worth the trouble... what you descibe is really like how pumpkins are grown on a mound, but that's not nearly raised bed gardening.
I've tried true raised bed gardening, but unless one is willing to spend a lot of money to have a number of them they won't be growing a whole lot... probably makes more sense to do container gardening. Raised beds are fine if all one wants is one or two very small growing plots but for anything more I think gardening directly on the ground in a large contained plot is far more efficient and economical. This is where I doubled the size of my vegetable bed:
I used cinder blocks -- two on each side -- to create a small, square, raised bed for a dwarf tangelo tree. Tangelo is a citrus (a cross between a tangerine and a grapefruit or pomelo) and needs excellent drainage, but my soil is heavy clay.
As I described earlier in this thread, I dug down about a foot, stirring superphosphate and gypsum into the soil. I then placed the cinder blocks with the holes facing up around the hole. Since I was only placing a single course of blocks, I did not anchor them. I then stirred ample amounts of course sand, peat moss, compost, and wood chips into the hole to raise the soil level to the tops of the blocks.
After allowing the tree to get established for a few months, I began a regular feeding program with high-nitrogen fertilizers since all the organic matter tends to remove nitrogen from the soil. The tree is doing well now and has even bloomed, but it has not yet set any fruit after some five years.
I packed potting mix (per my own recipe at ) into the vertical holes in the cinder blocks and planted wax-leaf begonias in the holes.
Because it gives you soil 30cm deeper than if you don't.
With that configuration and nothing to contain
It has not been my experience that the bed loses half its height or needs constant reforming.
D
Because it gives you soil 30cm deeper than if you don't.
With that configuration and nothing to contain
It has not been my experience that the bed loses half its height or needs constant reforming.
DFirst decide planting space length in your garden.Nail boards together, place in a level spot with plenty of sunshine.Cover the bottom with landscaping fabric, prior to filling with soil to keep weeds under control. Fill your raised bed with topsoil, compost and some potting soil. Work all these materials together.
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