By Benpcoleman
California,
United States 
Dahlia tubers from big box store - was already growing inside the packaging, a long a spindly stem with leave shoots. I just planted it but obviously it is all mangled. Can I cut them back to the eye or just let it grow and stake them? First time trying dahlias, and not expecting a lot of quality with these. Thanks!
22 Mar, 2015
Answers
This is how I was instructed to plant in containers! Start one third of the way up and fill in soil as it grows... No?
22 Mar, 2015
Potting up that way works for potatoes, Dahlia need sun and lots of moisture.
Do you know what type of Dahlia it is?
22 Mar, 2015
Hi, you can cut back the long, thin shoot to within half an inch from the tuber, and it will send out new sturdy shoots.
If you're going to grow Dahlia's in pots, you need quite large ones, put the tubers in the pots so that the old stems from last year are above the compost, with the tubers covered, and the compost should be about 1" from the top of the pot, { you're not earthing up potato's}, if you have a tall variety, put canes into the pot at the same time, as you may damage the tubers if you try to put them in later, keep them frost free, and put outside after the last frost in your area, Derek.
22 Mar, 2015
Thanks everyone! It is a "dinner plate" variety, but that's all it says! I think I will cut it, maybe raise it up a bit and put in stakes. Here goes!
22 Mar, 2015
Raise it up almost to the top, not just a bit!
22 Mar, 2015
They'll be OK. Hope you are not going to keep them in that pot though!
22 Mar, 2015