The de-husked ones can be sprouted, so I assume the one that still have a husk can too. But this depends on on how long it was stored and at what temps. I know its hard to, and it would be alot easier to buy a fresh one or like you said find one and try. Yet if your like me, thats the fun part :) I say go for it and let us know how it goes :)

- US_Marine

I think I read somewhere that a coconut only will sprout if it has completely ripened on the tree and fell off. Or picked close to that time. I'm guessing that the ones at supermarkets came from commercial growers and were picked early for long distance transport. Can't hurt to try. I'd be curious if you're successful.