Hello Capability :)
I've never heard of using wallpaper paste in baskets before..Lol! Not sure I'd risk it though. I just cut up old bath sponges and use them at the bottom of my baskets...seems to work OK.

You only need a tiny amount of water retaining gel per basket, and any surplus will keep til next year if stored dry. Well worth the £3-50 or so for a small packet, I reckon.

Thanks Puddleduck - great idea!

You don't need to go to the expense of retaining gels. I put bits of chopped up sponge in the base of my hanging baskets and pots. Any sponges used in the bathroom, usually go thru the washing machine first. Bit I cut them into small bits. You can buy a load from any £1 shop and use those. I've been doing it for years and never had a problem.

I'm curious about the idea of using wall paper paste - I can't see that it would hold onto water in the same way as the water retaining gels or crystals, surely it'd just make a gooey mess... even if the plants survived it.

You use such a tiny amount of the gel in each basket I can't see that it works out expensive. I cut a piece of capillary matting for the bottom of the basket and sprinkle a few crystals over it before adding the compost In this dry season I have even been putting a few crystals into each planting hole when bedding out and "puddle planting" to activate the gel. It has worked very well so far in a very dry bed. I transfer the crystals into an old jam jar to keep them dry.