Burnt clay clods

[Trevor Holloway]

This may seem a silly question but I'm prepared to be ridiculed if I'm completely off the plot (no pun intended).
On my recently aquired allotment the ground has a lot of clay in it, whilst digging over and burning off the bramble roots some of the clay clods went in the fire. Once cooled they come out like very soft brick, once broken into small pieces (they crumble quite easily) they look to be very porus and may be benificial in the raised beds to soak up and hold water.
Is this good or bad ?

[Beccy]

Well I can't say for sure, but I think good. You used to be able to buy what I can best describe as 'expanded clay' balls (think expanded polystyrene). They were sold as water retaining for use in trays of pot plants or in compost mixes.

You could experiment by mixing some granules into a sample of your soil then comparing it with a plain sample of soil as to how long they take to dehydrate. Will they sdtill make kitchen paper soften if it is shoved down into the soil might work as an indicator of whether the clay granules were releasing water.

[Compo]

I think that they are called aqualesha or something like that, and you are right Beccy they are clay basically so it's got to be worth at try, do a trial of two pots with lettuce in - one with granules and one without, use minimal watering and see which one does best.