should be ok , which sort are you thinking about planting in them?
Because there is so many varieties

I've got one Dahlia in a container adn it's just in multi purpose compo. I do add a fresh top dressing of compo in spring along with some chicken manure pellats and some blood fish & bone meal mixed in. It does pretty well, but they're not really container plants as they need a lot of water and tend to get buffetted by the wind in a container. It's a really big container too! If you look through my blogs I did one on Dahlias back in winter 08/09 and you can see a pic of my Dahlia in a container.

Thanks so much for your comments about dahlias! and also thanks Sid for those beautiful photos on your winter 08/09 blogs.
I was given about 6-7 dahlia rhizomes a few days ago. I've never grown any before and was thinking about putting some of them in containers as I am about to reorganise my garden entirely to give as much as access as possible to my elderly mum and did not want to have to disturb them more than once.
I read some information on planting dahlias http://home.howstuffworks.com/tips-for-growing-bulbs1.htm which advises that before planting them, one should
'Cut the crown longitudinally into several pieces, each with at least one rhizome and growth bud' Is this necessary or can I just plant them as given to me?
If so, what size container do you think is necessary? Should I plant one rhizome per pot or in a group? Questions and more questions!
Best wishes, saavikam (aka Alison)

Hi Alison, the cutting the crown thing is probably about propagation, which, as you're not yet experienced with these plants, I don't think you should bother about this time round. So just plant them so they are a few inches deep. Use the largest containers you can get away with as this will give your plants the largest root run. You will probably end up watering every day in the height of summer as they get quite thirsty. I'd defo say just one plant per pot, although some Dahlia plants are larger than others. If you've just got the bedding sort, then you could put, say, 3 of those togeter in a large pot. Did you see in my blog the deep purple dahlia in the container in my drive? That's just one tuber!! The container is about 50 or 60cm across the top.

Thanks Sid for the very prompt and helpful info!
I'm off to buy some containers today and hopefully will have them planted by tomorrow. Take care, and thanks again, Alison