Maris Pipers are a main crop potato so you need to give them 14 - 16 weeks from planting to harvesting. As to whether you will get anything only time will tell! Make sure you keep them well watered.

Don't expect a huge crop unless you feed them a great deal if growing in sacks or bins. Unless it's impossible, or you just want to try out the bin or bag method, always grow in the open soil as you will always get better results if you have a half decent soil. Don't believe the hype about getting a sackful of spuds out of a single bag or bin, because in my experience you are lucky to get a good Sunday lunch's worth!

Have to agree Bertie the year we tried it was a waste of time... tatties in the ground are so easy!

Depends entirely on the variety as to your crop, not the ground.
Under identical conditions, last year my red duke of york produced a crop of marbles. Casablanca produced a crop of footballs.
Grown properly in bags, one bag will produce more potatoes than those grown in soil.

Thanks for the replies, I shan't expect too much then.
But I will report back when I check them out.
Just one question - with what should i have been feeding them ?

To begin, I would only entertain growing earlies in bags. The advantage is that it is a shorter cropping time, they will be expensive to buy and maincrop potatoes will be cheap in the shops. Also you can start them off in a cool greenhouse, bring them outside and easily fleece them when frosts are past. Growing earlies leave them less suseptable to blight. The secret seems to be that you need to feed and water them on a regular basis. Yes, it take less management if grown in the ground but many people don't have the space and would rather use a limited space for more profitable crops. My first attempt was with Rocket, which turned out to be tasteles but Sutton's Foremost did the trick for me.

Got it Jimmy, I'll do exactly what you did, including the Sutton's Foremost next year. Thanks.