[kermit]

Ive used them for 3 years, along with other large containers (spare recycling boxes are the best).  All together about 8 containers of this size kept me, wife and son in new (1sts and 2nds) potatoes from late June until late Sept last year. 

Key benefits:
potatoes come out absolutely perfect
big crop (swift, charlotte, lady christl) - bigger crop than neighbour (same seeds and location) who grew in ground.
saves precious raised bed space if you are growing in a small garden like me
can cut off dead foliage and keep in sack (under the soil) until required


Drawbacks:
expensive to fill if just using MP compost (try soil plus fertilizer / manure) - but remember can re-use compost to dress other parts of the garden.
i was watering every day if didnt rain (used water retaining crystals last year which helped)
As for cost, probably no cheaper than buying from supermarket, but I would pay twice for having a ready supply of fresh, organic, tasty tatters out the back.  Nothing like coming home from work and never having to do the 6pm supermarket sweep on the way home every night.

My advice - go for it.  JBA website will tell you if they sell them or not 

[joyfull]

for those of you who have tesco clubcard vouchers they have this on offer for potatoes and the grow bags:-

http://www.tesco.com/clubcard/deals/browse.aspx?N=4294963362

under kitchen garden kit

[billathome65]

I bought some bags as part of a promotion as I have very little space to go with a main crop of pots. However after saying that I am hopping to have some spare ground to do a crop in just to see which is best as I'm new to all this gardening stuff I am just experimenting at the moment.

Bill

[JaK]

I grwo spuds in those bags each year and always get a good crop. I don't have the space to grow spuds int he ground so this is by far our best option.

[Trikidiki]

I think they're great, although have a look on e-Bay, they're much cheaper there.

Especially useful to get them going early in the greenhouse, mine's unheated so I keep loads of fleece handy. They go outside when I'm ready to plant up my tomatoes in the greenhouse. They have good handles which make them easy to move.

I also grew some Oca in them last year and am planning to try sweet potatoes in some this year.

I use home-made compost or spent growbags in mine. Mix in some BFB at planting time and add some more to the compost used to 'earth-up'.

I do agree that watering has to be quite thorough.

[Ma and Pa Snip]

Well I am going to buck what appears to be the main consenus of opinion here.

We've used bags for 3 years now, first year tried maincrop and was disappointed with the crop. Since then use them for salad type, such a pink fir apple, and first earlies.

 Yes I agree we did not get the same volume of crop as out of the ground but worth the effort of using some of the homemade compost to fill them.  Just dont try overplanting.

Someone referred to large builders 'tote' bags, hmmm nice idea but try emptying them to get the crop out !!!! dont leave it til the last minute when you want some nice fresh tatties for sunday dinner, hard work or what.

[Jamie Butterworth]

Thanks for all the advice everyone, have just watched a few vidoes on the JBA site and am impressed, will order some soon

[digalotty]

jamie if you have a homebase local they do potatoe grow bag kits for £5.99 you get 3 bags and 3different variety of potatoes to go in them total 9 spuds and iff you buy 2 kits they are £10. 
i used them last year and was pleasantly suprised

[bigben]

I sow direct and in bags - tend to get less slug damage in bags but this might be because I tend to use bags for earlies.

 As others have hinted-  the problem with bags is the cost of filling them. I have a large plastic compost bin of about 400 litres which I fill up toward the end of the season just for spuds. I then supplement this with a few bags of manure which is free if you take your own bags and then add some B&Q multipurpose 3 for a tenner. So all told I get about 600-700 L of growing medium for about a tenner. This will do me more than enough pots.

[rhysdad]

In a mad moment last year i bought nine of the wretched things. By the time i'd forked out for seed potatoes, compost and fertiliser, i reckon it cost me about a fiver a kilo and whilst the spuds were nice, they weren't that nice.... I wouldn't bother again  TBH, i'm not sure i'll bother at all with spuds on my lotty. One of our farmer customers sellls me a bag (25kg) of un-irrigated Marfonas for a fiver and very nice they are too. I can't really justify the bother, and worry re blight, of growing my own....