Apparently you can use the gel from disposible nappes instead of expensive water-retaining gel crystals in the compost of hanging baskets, to reduce watering. Split open the nappy and mix the gel with the compost or cut up the nappies and put at the bottom of the basket. (If they have been wee'd on, all the better - good for the plants.)
Sounds like a tip from Viz.
Haven't tried it myself - no baby and no hanging baskets