Potatoes Please

[OnlyWantsOne]

Brought some maincrop seed potatoe things (havent done this before) and instead of the grow bag type things for spuds, bought two large plastic tubs for them.

Instruct, what do I do, how deep as the tubs are about 2 feet deep?

[throckenholt]

out a layer of compost in the bottom, put the spuds in, and put a bit more compost on top. As they grow keep adding compost (like heaping up with ones in a conventional bed).

[OnlyWantsOne]

but how many layers can I bung on top of them, my pots are two feet deep, if I say, put the first potatoes on 4 inches or so of compost, that leaves a lot of growing to do before they are allowed to actually leaf up without me mounding more compost on them?

[throckenholt]

I think you can probably keep mounding them up until they don't look happy.

Apparently you let them grow to about 6 inches above the soil, then put 2-3 inches more soil, and carry on doing that, til you get near the top of the tub.

I have heard of people growing them in half barrels.

[Compost]

you don't wait until the leaves are 'out of the pot', Just about 6 to 8 inches of plant leaves, then earth up , and continue on until you are at the top.

[OnlyWantsOne]

and they'll go all the way to the top?

They are about the size of half barrels actually

Whats the best compost / soil?

I am not filling them up with John Innes number 3 like the girl at the garden centre told me to

[minxpinx]

Yes, they will get to the top - I planted mine in the same things about 6 weeks ago and they are nearly at the top now. I've heaped up soil on them about 3 times. Make sure that you give them plenty of water.
I've just been using some stuff from an old grow bag with some fertiliser mixed in.

[OnlyWantsOne]

How big do the little shoots have to be when I first plant them?

They are currently about 1cm - 2cm

[minxpinx]

That'll be fine.