Conkers

[hairygrape]

My son has just come home with a load of spike laden horse chestnut husks. He has asked when he can cut them open to reveal a conker - he knows that right now, they just contain a white nut. The husks were cut off a horse chestnut tree by his mates. Now as I understand it, the traditional brown conker can only be extracted from husks that have fallen from the tree and are lying on the ground. Although the husks he's brought home are large and spikey, they are not going to contain a mature brown conker as it's too early in the year.
So the question is, can I keep these husks indoors until later in the year and open them to reveal a hard brown conker suitable for playing the game or will this never happen? I can't find any advice on this on the Internet.

Thanks

[FatticusInch]

Never happen. Now they’re removed from the tree in their unripened state that’s how they’ll remain i.e. they’ll grow no further.

[Chipchopper]

The fruits of the horse chestnut tree are programmed to split the husks, as they near maturity, at this stage, they will turn brown when they are exposed to the open air, many of them will be buried by birds and squirrels to be dug up later when foraging for food a small percentage will be lost or forgotten and grow into new trees.
So, I would recommend that the conkers are collected when they have ripened and turned brown.