[oldtimer1]

Hm there is a big problem with nappies they reckon they will take over a hundred years to break down in landfill. Just the base material will rob nitrogen if chopped up in top soil. Most makes have residual dioxin in them from the bleaching of the fibres. I wouldn't want anything like this near any plant I was going to consume. In addition some of the newer makes have water absorbing polymer granules inside a membrane in the crotch area. Basically they are polluting the environment big time.

You can buy polymer water retaining crystals made specifically for mixing in compost. There are two types sodium based and potassium based, for cannabis the potassium based ones are the best. As both types release a small amount of the base chemical every time they go through the charge discharge cycle and as we know cannabis does not like salt. There are also other long term chemicals released over time as the polymer degrades. So I would not recommend its use for the organic gardener. Neither would I recommend the use of sponge as its a soft coral on the endangered species list. Nor any household artificial sponges made by the plastics industry, only because I have no idea what the breakdown products might be.

The only thing I can recommend is course ground seaweed mixed through the soil, this works like the artificial polymers but is no where as efficient, but at the end of the year it has completely broken down into organic macro, micros and trace elements and it will improve your soil no end as well as feeding the soil micro fauna.