On Apr 8, 11:49*pm, K wrote:
Adam Aglionby writes

On 8 Apr, 15:42, Chris J Dixon wrote:
Adam Aglionby wrote:
Thanks David, Aldi has an offer coming up with a pretty good price on
silica gel, will give it a try:

http://www.aldi.co.uk/uk/html/offers/58_5611.htm

I think you may be mistaking the water retaining gel used in
gardening with silica gel which is used to maintain a dry
atmosphere in packaging etc.

http://en.wikipedia.org/wiki/Silica_gel

Under the impression they are both the same, certainly seen one sold
as the other?

I sincerley hope not. Silica gel is a moderately aggressive gritty
inorganic dessicant used to keep sensitive equipment dry. You have to
heat it up in an oven to get the water back out of it.

Water absorbing gel is a particular sort of organic polymer with a
high affinity for water. It will give the water back to plant roots on
demand.

I thought the water retaining gel was basically the same as the stuff
used in babies nappies. Very different from silica gel.

Indeed they are typically an acrylate-acrylimde copolymer. eg.

http://www.puhuaind.com/yw_version_e...FQZRMAodvjjjCQ

(not a recommendation for this source - they were the first Googlehit
with the product and its chemical name)

Cheap, virtually harmless but not Organic(TM) by any stretch of the
imagination.

I prefer compost or manure for adding organic material to my soil. I
might consider using this stuff in hanging baskets where water vs
weight tradeoffs are at a premium, but not as a garden soil improver.

Regards,
Martin Brown