[Tenhens]

Have been reading the page on potato growing in bags which says that main crop don't do very well ,why is this?
We have grown Charlotte's for the last few years with good results , looking to expand this to main crop.

[mumofstig]

Probably because some of those varieties can grow very tall, and being in the pots for so long, are likely to need a lot of extra feeding & watering, for the same reason.
If you can fix up some wire mesh above the bags/pots, so that the foliage can grow through and still be supported, that works well, and solves the first problem.
Then it's just up to you to keep up with the feeding/watering regime 
I grew some decent Cara in 35L pots last year, but it was a struggle keeping up with the watering, cos it runs through so very, very quickly.
Good luck if you try it.

[steven c]

we also grew Cara in pots varying 55 -70 litre we also struggled to keep watered [it was very hot and dry last year] but we did get a good return in the end. trying same again this year with saved seed potatoes.

[Grubbypaws]

I grew Setanta in 50L pots. they did need supporting and watering but I am still enjoying eating them now! Well worth the effort.

[Snowboar]

Like everyone else says watering

[Browseruk]

we also struggled to keep watered

My grandmother pricked a tiny hole inthe lid of a two litre pop bottle; filled it with water and 1/3rd buried it in the pot/growbag, upturned next to her tomato plants/flowers etc. Each fill lasted 2/3 days.

Anyone else done this?

[steven c]

we use vending machine type plastic cups with a small hole in the bottom buried next to tomato plants in builders buckets fill these with water this puts the water to the roots i think top watering in hot weather a lot will evaporate but we feed from the top.  the water doesnt last as long though gone in minutes not days maybe new cups with much smaller holes would help.