Gardening Questions How do water retaining gel crystals work ?
How do water retaining gel crystals work ?
Asked on 2 May, 2008
While reading the Letters Page in last week's Amateur Gardening magazine I came across a question about water retaining gel crystals. It has left me wondering.
Like the author I think I can remember some years ago seeing Magnus Pyke showing television viewers that no matter how hard he tried he couldn't get any water back out of the gel. It would appear the gel works while the compost is moist, but as the compost dries out can plants' roots access the water contained in the gel ?
If we have to keep the compost moist anyway for the gel to work why are we using it?
I thought as the compost dried out it absorbed the water from the gel .... does anyone know, how does it actually work ?
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Replies
2 May, 2008
Yes, the same material is sold as a dehumidifying tool. It does absorb moisture from the air. You can dry it out in the oven, but if it's gone completely liquid it's probably too late.
I don't know the answer to Xela's question. At a guess, the gel for gardeners is slightly different to what Magnus Pike had, so that it does release moisture at the right time.
2 May, 2008
Oh! Thanks for that, Ukslim. Wish I'd known that before! Thought I was going mad - kept looking for leaks in the greenhouse roof - thought water must be getting into it somehow!
Joined 29 Feb, 2008
Hereford
2 May, 2008
This is very interesting, Xela. I don't know the answer, but I do have more questions! I bought some plug plants this spring which were sitting in trays of water retaining gel. Rather than throw it away, I though instead I would dry it out and keep it until I needed some gel in the hanging baskets. I left the trays on a high shelf in my greenhouse, expecting them to dry out pretty quickly. However, they actually seemed to get WETTER! i think they were absorbing moisture from the air, at they just got wetter and wetter until they became completely liquid. They're still sat there. WHAT'S THAT ALL ABOUT???!!!