Planted sprouting potatoes in early may - now what?

[hermioneweasley]

I put some sprouted little potatoes in soil in early may. Huge green vegetation coming out of the soil now. What do I do now? I have tried looking up advice online and am utterly confused. Planted them in a tall, narrow container.

Thanks!

Just keep heaping soil up around them to cover the roots

Oh...I haven't planted them that early so not sure if they're ready yet. I grow later ones and dig them up once the foliage looks dead.

Thanks, so keep covering up the green stalks of the plants that have come through and then dig them up when the plant is dead?

Thanks for your help