Re: keyhole beds?

[Toby Hemenway <hemenway@jeffnet.org>]

Mikal wrote:

> Anybody have opinions on keyhole beds?

I've got a combination of rectangular-raised beds and keyholes, and the
keyholes get a mixed review from me (which is embarrassing because 3 years
ago I wrote an article for American Gardener magazine unabashedly extolling
their virtues). Since the "hole" is in the middle of a 7 to 10-foot-across
circle or square, they definitely give you a large, unbroken expanse for
planting, something I've not read in others' description of them, and this
allows  for some nice combinations of plants to fit into a small but
contiguous space. Usually they are sold as a good way to reduce path length,
but in actual practice, I've not seen that path area is reduced much since
often there needs to be access to the _outside_ of the keyhole or mandala as
well as the inside.

Keyholes also require a shift in irrigation methods (we have 90-day droughts
most summers, a la the Meditterranean). I use T-tape in my rectangular beds,
which is very cheap. Since T-tape can't bend, the keyholes need either 1/2
inch hose with emitters, wound into a spiral, which uses a lot of tubing at
$20 per 100 feet (one bed can gobble up 30-50 feet) or a mini-sprayer of
some sort in the center. As the plants grow I'm constantly having to raise
the height of the sprayer since it gets buried in the leaves. And a lot of
crops don't like water on their leaves. Sometimes I just leave the T-tape in
place, running it across the paths where it gets trampled. Anyone got
suggestions for a drip system more suitable to keyholes?

If you've got a circular or square garden on fairly level ground, keyholes
may work well. I find in a rectangular garden or one on a slope, I'm always
trying to get where the keyholes won't let me. One place they've worked well
is in my greenhouse, 14 x 24 feet with a central path and keyholes coming
off the path. I defined the path and entry to the keyholes with cedar
boards, which keeps things neat, and it's a small enough space to water by
hand. 

>I'm concerned with the
> idea of "one visit" crops being so far back that harvest requires walking
> in the bed.

I set a board on the ground to walk on. This is also why many keyholes
eventually develop a set of paths on the outside of them.

>What about weeding, mulching, checking drip lines and so on? It
> seems like these activities will mean lots of trampling unless the whole
> thing can be reached from paths.

Make the bed small enough to reach across much of it easily; it's common to
make them too big. In general, I like keyholes for small quantities of mixed
species. For big production crops, I've returned to rectangular beds.

Keyholes are a bit like the other whiz-bang garden idea in Pc books: herb
spirals. On a tour of about 20 Pc sites, I saw 5-10 abandoned or overgrown
herb spirals for every one I saw in use (I just tore my own out a few days
ago). Anyone else found this?

Toby