Re: bed size
I ought to just lurk, but thought I'd join the discussion of raised beds,
since I'm in the middle of preparing a bunch of them.
I agree with Adam that the Nobel website is a very good one, especially the
discussion of how the depth of good soil is vitally important, since most
veggies take most nutrients and water from the top 30 cm. This idea goes back
a long way in both the East and West, and there are lots of good methods (I
first learned Alan Chadwick's 'double digging'). Interestingly, there is a
counter-current in gardening that suggests minimal soil disturbance is better
than deep digging (Fukuoka, among others), but either way you don't want to
walk on the soil, so beds make good sense.
The shape and 'edging' of beds is another matter. First off, raised beds
require no edging of any type - tires, lumber, or anything else. You can
simply berm up the soil. This is what commercial-scale vegetable production
does. Even a 1 m wide bed will easily 'hold' being mounded up 20 cm in the
middle, if you protect with mulching.
Still, I like to edge, especially on a slope. But I don't like rigidly
straight lines. A 1 m x 2 m rectangular bed looks like you need a headstone
inscribed 'Here Lies Fido'. To created edging for curved beds, I like to use
stone, which I get free by picking it up along roadsides or for about $10 a
ton at a local rock quarry. I use a basic 'dry stack' method. In urban areas,
you can use trashed concrete. One garden that did this beautifully is the
Martin Luther King School garden in Berkeley, CA. Gardener David Hawkins had
kids link hands to form the shapes of beds, and the result is both very
pleasing and straightforward to manage.
The Nobel site does have a good discussion on bed shape for market gardening.
For market gardens, a more 'rectilinear' layout might make life easier at
times. Market gardens in West Africa I saw in my Peace Corps days were laid
out this way, same goes for many Asian and French market gardens I've seen.
But in gardens for personal production and pleasure, curves seem a more
natural and pleasing choice.
'Beds' are not the only way to arrange plants in the garden, either.
Fencerows provide 'free' trellises, and define the viewscape of the garden.
Since you can only access a bed backed up to a fence by approaching one side,
'fence beds' need to be narrower than beds with 2 sided access. Some crops,
like fruit trees, work much better in oval, triangular or organic shaped beds
than rectangles. And some crops - corn for instance - are easier to manage
(for me) in blocks intercropped with hills of squash and beans than if I try
to shoehorn it into a 'classic rectangular raised bed'.
So, I think bedding is best seen as one technique among many in shaping a
garden. Bed shape can vary enormously, depending on the situation and person.
'Raising' the bed (creating a deeper layer of well prepared soil) is a very
productive technique for vegetables that can improve yields and make care and
harvesting easier (it is labor intensive when starting, but, honestly, not
that bad...esp. considering the payoff). And gardeners can use a wide variety
of local materials to 'edge' or stabilize beds.
Three things I wouldn't use, personally, to edge raised beds are CCA treated
lumber (the green stuff treated with arsenic-we are addicted to it here in
the South, I'm afraid), lumber harvested non-sustainably (this often means
redwood out west, I hear), and, yep, tires. We need to do something with
tires, but this isn't it, in my opinion. They look gross. Shredded tires now
pushed as playground mulch off gas in hot weather and really stink. I might
use tires to help stabilize a steep (>30%?) slope and form terraces, if
nothing else were available, otherwise, I wouldn't use 'em, personally,
regardless of the leaching issue (and, frankly, I don't trust that they are
To be fair, tires do make these cool traditional Southern planters: You turn
one tire inside out, cut it like a flower (optional), set it on 2 or 3 more
tires, fill it with dirt and plant into it. To spruce it up, you paint it
white. Before I did the Nobel 'raised bed', I'd try 3 or 4 of these for
tomatoes. You could even do tomatoes or potatoes on blacktop with this, I'll
bet. Worth a try...
In a message dated 4/18/01 10:14:48 AM Eastern Daylight Time,
> This is a great detailed link. It's chock full of great information and
> author Upson's step-by-step approach is extremely helpful.
> Upson discusses discarded tire reinforced boards which sound great. My
> concern... Are discarded tires and the chemicals used to manufacture them
> inert enough not to leach into the soil? We have piles of mosquito
> collecting used tires in a back yard of a garage near two community
> that we're going to be renovating/merging. If the tires are inert enough
> for gardening purposes, it could be a good choice for us. Please let me
> your thoughts on this,
> Adam Honigman
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