"john royce" wrote in message
...
My small front garden is mainly populated by pots.

Novice also wants to grow some pine trees and bamboo in these small cold
water storage tanks.

See pictu

http://tinypic.com/view.php?pic=2192hyt&s=5

These tanks are 45cm (18") x 33cm (13") x [30cm (12") high].

Since i will only water the garden about once a week, it would be ideal
not to put any drainage holes in the tank, so any rain would *all* be
collected in the pot. But since i'm afraid of causing rot in the roots, i
think i must have some drainage holes.

I have found in the past that the roots find the holes after a while and
go down into the soil, causing problems when i want to move things around
at a later date.

So what I thought I would do is put some drainage holes in the *side * of
the tank. Then I can easily see if the roots are pushing through.

The question is; how high up the side of the tank to put the holes? If i
put them up say 3 or 4 inches from the bottom, it would trap a bit of
water (like these 'so called' self watering pots).

Would that be about right? Any higher would be better in that it would
retain more water, but would it cause root rot? Grateful for any
suggestions on the best height of the holes.

You really need to learn more about your plants first. The pine and bamboo
may
have different watering (and soil!) requirements. If they do, you may not
be able to plant them together, if that was your intention. Also, you can
build in drainage by putting stones or polystrene in the base, which will
also save you money on compost. You will need a soil-based compost, btw, to
give the tanks stability in windy conditions.

As Ron says, you could still drill holes in the bottom and place the tanks
on brick stacks. This is actually a very good idea because, in winter, the
rootball will be protected from the icy ground. It won't protect the sides
of the tank, though, so you'll need to plan for some winter protection.

If I were you, I would err on the side of dryness. More plants are killed
from over-watering than from dryness. You can always add water, but you
won't find it easy to wring the rootball out when it gets too soggy. You've
obviously thought about this, hence the question, but the only time I use
side drainage is when I'm growing bog plants or marginals. By all means
experiment, but not on valued specimens. If you still want to try, look at
the 'self-watering' pots you mention. The water reserve isn't that deep, is
it?

Hope this helps.

Spider