Why do you earth up potatoes

My potatoes seem to be growing well, Charlottes, I have earthed them up a couple of times. Can you tell me why we do this and when to stop please?

 

Earthing up increases the length of the stem under the ground and it's the underground stem that produces the potatos. The end result is a bigger crop.
Wait until the plants are about 10cm tall and then earth up to almost cover them. You can do this about three times at intervals of two or three weeks.

 

Thanks Dave, I better do them again tomorrow then. Lin

 

I agree with Dave earth up as much as you like but once flowering stop then. It also stops spudgums going green and giving you belly ache.

 

Stem produces the potatoess
Potatoes that grow on the surface turn green, so increasing the soil depth helps

as has been said.

Earth up and cover the leaves is frost is forecast, as that will kill the tops of the plant and set it back

I earth up until I can't get any more soil banked up. For me that's long before they start flowering.

I only earth up when frost is forecast - so I let the plant grow, as much as possible, without earthing up. My First Earlies have already been earthed up as much as is possible. The maincrop are barely poking through the ground, they will be fully earthed up by around 1st June.

Even with earthing up I find that potatoes still form on the surface, and go green, so after they are fully earthed up I put down a thick layer of grass clippings. I do this before the plants are so big I can't get between the rows. It needs to be a thick layer because it will be at least a month later before the spuds are harvested, and the grass clippings will shrink down in that time. Don't use grass clippings from a lawn treated with selective weed killer