drainage in pots

Rodger Whitlock totototo@pacificcoast.net
Tue, 15 Feb 2005 17:47:00 PST
On 14 Feb 05 at 0:15, Alberto Castillo wrote:

> ...better than round holes are vertical slits... Unless your
> containers are on mesh benches (and who grows their plants  this
> way I wonder?) the bottom holes are useless. When people say that
> they are growing plants in such and such container size it is
> seldom true. Only the upper fraction lets roots survive. Half or
> 3/4 of the pot is saturated with water and roots would not venture
> into it. If you plant your bulbs deeply the roots will drown and
> rot will set in from the dead roots to the basal plate and it is
> all over. To avoid this you must exclude excess water that collects
> by gravity in the bottom of the container taking a long time to
> pass through the bottom hole: a few round holes even in the side of
> the pot are often not enough. Hence the long slits.

What about pots plunged or placed on sand so that the soil in them 
is in capillary contact with the sand? I used to have ordinary terra 
cotta pots plunged in sand (placed over the soil) and was of the 
opinion that the sand bed blotted up excess moisture after watering, 
while providing some moisture when things started to get dry.

The key element being that the pots had no crocking in the bottom and 
were wrung into place so that there was capillary contact between the 
soil in them and the surrounding sand bed through the central drain 
hole in the bottom of the pot.

Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate

on beautiful Vancouver Island

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