Water retention crystals in gardening

[WendyS]

As a keen organic vegetable grower, I'm upset we've just had a hosepipe ban imposed and plan to incorporate these crystals into the soil in my veggie patch to retain moisture as our soil dries out very quickly. Does anybody have experience of using them on a widespread basis (other than in patio containers & hanging baskets?). How long do they last for and do they contain any harmful substances? Thanks.

[logman]

I have used them in tubs, hanging baskets and tree planting and found them quite useful, and like it says on the packet you only need to use them sparingly.

If you get a heavy down-pour, the crystals grow up to the surfice and are jelly-like and swollen to about an inch in diametre..