Clay Ball things.

[Kirk]

I have half a bag, big plastic sack type thing, of expanded clay "balls". About 8mm diameter and hard.

Sort of useless to me, no idea why I bought them back in the mists of time.

Can I dig them into the ground/soil and will they break down. Thinking get wet and revert in time to something like clay dust. Or will they still be hard round balls until the sun goes to red giant and nova in about 5 billion years and most survive that small event.

Posted here as not sure where else. Nowhere seems overly applicable.

[gardening_gal]

Sounds like the kind of thing used in hydroponics? Did you ever toy with that idea maybe but never went ahead?

You can use them as a drainage layer at the bottom of containers, good for the plant roots. Or also as a 'mulch' on the top to help with evaporation and the plant drying out too much. They will break down eventually though.

[Snadger]

If its calcined clay it is normally used in drainage as a backfill to get water away from surface to drainage pipes.Theoretically it shouldn't break down.