Re: Drainage in large pots?
- Subject: Re: Drainage in large pots?
- From: J* R*
- Date: Wed, 2 May 2001 10:25:35 -0700
For drainage you need particles of varying sizes and uneven shapes.
Beach sand and rock dust are both fine, smooth particles, as is clay.
Try "sharp sand" or very coarse sand, and gravel, as up to half of
your mix, or more depending on what you are growing in it. Perlite
is lighter in weight, if you use it, be sure to get the large chunks
(I think called "Lava Rock" not the fine, dusty stuff.
And with quarter inch holes in the bottom, I'd put a layer of coarse
gravel on the bottom, covered with screen cloth the keep the chunks
from clogging your holes.
These are tips from succulent growers
Jane Reese
Santa Barbara CA
>I have a bit of a gardening mystery. I live in rainy western
>Oregon, with heavy clay soil. The drainage is good, for clay, but
>there are a few things I grow that need drier roots. I decided to
>create a large planter for things that need better drainage. I took
>an old metal wash tub, drilled some quarter inch holes at the bottom
>(the biggest drill bit I had), and filled it with the following mix:
>
>one part perlite
>1/2 part beach sand
>1/2 part rock dust
>one part compost
>1/2 part funky commercial potting soil (basically peat, mixed with perlite)
>1/3 part dirt from the yard (mainly for worms, microrganisms, etc.)
>
>In other words, I put in a little bit of everything I had lying
>around :-). I gave it a good soak with the hose, and to my surprise
>it didn't drain at all! The water just formed a big lake on top,
>wth perlite floating in it. I put sticks into the drainage holes to
>unclog them in case they were clogged; I dug holes from the top down
>to the drainage holes; no help. Eventually the lake diminished bit,
>but it didn't seem that any of it came out of the holes. I dug
>around in the center of the pot, where I found that the mixture was
>damp, but not as wet as the top and sides. In other words, my new
>mix is ABSORBING a huge amount of water. Not exactly what I
>intended. So I guess it's clear by now that I know nothing about
>soils :-). Can anyone suggest what I can add to this, or what I can
>do starting from scratch, to make something that will drain more
>quickly?
>
>--A very baffled Susannah
_______________________________________________________________________
Jane Reese
E-mail: jreese@silcom.com
