On 16/08/2014 23:36, Bob Hobden wrote:
"stuart noble" wrote

Chris Hogg wrote:
Spider wrote:

I have been wondering about using Hydroleca as a substitute for aquatic
compost when potting up pond plants. There's probably a very good
reason
why I've never heard of it being done, despite its being used for
hydroponics. Perhaps it's too light? I'd be interested in other
urglers' opinions/experience.

Never used it, so can't answer your question, but Hydroleca is just a
trade name for Lightweight Expanded Clay Aggregate (the Leca bit),
widely available and probably a lot cheaper than Hydroleca. See
http://tinyurl.com/owjjpe5 for general info. At one time in Cornwall
large quantities (many lorry-loads) were used as fill in 'escape
lanes' at the bottom of long steep hills where lorries whose brakes
had failed could be brought to a reasonably safe halt. And no, I never
did avail myself of the resource (but I bet some did!)

If it does turn out to be a bit light (it may even float; it has a
malteser-like structure), you could always mix it with gravel to
weight it.


Allegedly it holds 40% of its own weight in water, which isn't a lot
comapared to vermiculite, but enough to stop it floating.


I used it as a filter medium once and some of it will float but it will
all be too light to use in a pond, the fish will have it out of the pots
in short order.



Thanks, Bob. That definitely rules it out for pond use, then. If half
of it sinks and half of it floats, I'll be forever netting it from the
pond. Silly idea abandoned :-}
--
Spider.
On high ground in SE London
gardening on heavy clay