What compost mix for poataoes in sacks?

To get the other half involved in more hands-on gardening I've bought him a set of 3 potato sacks and seed potatoes.  It was a little late and they've not chitted too well but I think they need to be planted now to have any chance.

What compost should we use?  I was thinking along the lines of peat-free shrub & tree, garden and mushroom.  Anything in that to sacre the horses or anything missing?

Any help gratefully received - I'm a flower gardener not a veggie!

a general all purpose compost will be fine,put about 4 inch in the bottom of your sack and then put your potatoes in.Then cover the potatoes with about 1 inch of compost and water.As the potatoes begin to shoot and the shoots show through the compost add more to cover and then just continue like this until the sack is full to about 2inch from top (this helps hold the compost in when watering.Remember the green shoots are frost suseptable so always keep them covered in compost for the next few weeks Also potatoes are all water so never let the compost dry out   hope this helps oh and dont forget to buy the lurpac when your next at the supermarket.

You don't cover the foliage forever.  After a bit you allow the top to grow into a bushy plant.  This year I am trying something new with my sacks.  I planted the potatoes near the bottom of the sack and then filled the sack up to the top straight away.  It appears to be working because they have just started to poke out of the top.  It was a lot less hassle.  Mine are growing in a mix of half New Horizon multi purpose and half compost from my compost bin.

Great tips - thanx guys.  Lurpac on the list

KG mine have just started to poke through, do I need to cover again?

You can't tell from my photo, but those sacks are three quarters full of compost.  I would suggest that you keep earthing them up as they poke through until your sack is about three quarters full (if you are using sacks the same size as my used compost sacks).

Thanks KG mine are also 3/4 full just wondered if I should keep going.

I'm not earthing mine up any more now.

ours will be well behind yours then - only planted them last night! 

By the way, do I need make a couple holes at bottom of the sacks for drainage?

Yes, I cut several holes for drainage.

Thanks for the reply.