Earthing up - is it necessary?

Robmarston

Hi, I’ve planted some first earlies deep in a raised bed, as recommended by Monty. I also planted out my maincrop today in a shallower raised bed but just as deep. I understood that earthing up was to protect from frost. If there is no frost, and you plant really deep, is earthing up necessary when the shoots come through?

Hostafan1

Earthing up is more about stopping light getting to the developing spuds, that's what turns them green and inedible.

Robmarston

So in effect you’re just putting a heavier layer on top to ensure darkness? Would black cloth then do the same thing?

Hostafan1

old compost bags, grass clippings( but not rigth against the foliage ), they all help, but you need to make sure NO light gets through.

Robmarston

So potatoes form near the surface of the soil? If they weren’t earthed up, would only the top layer turn green and be inedible, or would this also affect those lower in the ground?

Hostafan1

Robmarston said:

So potatoes form near the surface of the soil? If they weren’t earthed up, would only the top layer turn green and be inedible, or would this also affect those lower in the ground?

only those which get light onto them, those below are fine

GemmaJF

There are a couple of additional advantages to earthing up, often additional potatoes form from the newly buried stems and it also helps to protect against blight. I personally think it helps a lot when watering as the plants can have plenty to drink and the mounds ensure the tatties are not sitting in water.

In a no dig situation, covering with black plastic early on and making a slit for the shoots to grow though works. The sheet is then lifted to reveal the tatties underneath. It will not produce the same yield as the traditional method though.

Dovefromabove

Yes if you earth up you get a bigger crop. 🥔 🥔 🥔 
Doesn't really apply to first earlies as they’re not in the ground long enough. 

Skandi

If you're growing earlies don't bother, but if you want big maincrops you will need to as they push up to the surface as they grow and will go horrible and green if you don't cover them with something, but it doesn't have to be soil. I have done potatoes by dropping them onto the soil surface and then covering with straw, it works but voles and slugs can be an issue.

Allotment Boy

In the no dig method you can "compost up" ie put a thick layer of compost on top instead if you don't want to scrape the soil up. Green potatoes are poisonous so must not be eaten.

Smudgerii

cover with cardboard, make sure to wet it thoroughly.