Do you know how big it will get? That would really determine pot size. And for soil: mine are not picky, any well draining potting mix (not a fan of MG, but it works fine).

Generally- they do better in the ground and they are easier to water that way. I use MG on mine every week at full strength, but many other generic fert. will work.

AS far as staking, you can use a lot of different 'things' upside down tomato cages, plain bamboo stakes, bammboo T-Ps ect. Just be really careful you do not pierce a tuber when you stake them.

Also- can you just move it to the shade when you get really hig temps? Mine wilt in the noon day sun but come back after 4 pm or so.

Let us know about the mature size

Keriann~

Was it sold as a planter?

I would put it somewhere that perhaps it is shaded during the hottest part of the day.

I would also plant it outside of a pot. For a really large plant like that, the pot you will need is huge!! I have a neighbour that grows large Dahlias in planters very successfully, but urns are HUGE!!! Must be nearly 10 gallons!!

I have heard tomato fertilizer is good for them. My MIL uses MG with great success... I tend to forget and all mine grow fine. I have heard that high nitrogen can cause the tubers to shrivel up when they are recovered in the fall, I would suggest laying off it at the end of the growing season if you want to recover the tubers in the fall. I have also heard this is when they typically do most of their growing, in cooler weather.

Dahlias like soil that is not wet. It sounds like it either does not have a good root system yet, probably due to the pot being too small, or the sun is just too overwhelming in the zone you are in.... I don't know much about zones and dahlias past zone 6 though.

My dahlias like really dry soil. I have them close to the house and they get almost no moisture and lots of sun.... Your biggest challenge is probably that the pot is too small.

thanks so much for responding!

@keriann - i think it's going to get pretty big because it's already about 3 feet. i ran out and got some miracle grow (MG?) bloom booster and a general fert for flowers. i'm gonna take a chance and put her in the ground. we have a heavy clay soil, but i've amended it hopefully pretty well. i'm gonna experiment with different staking options and ties. thanks again!

@homemommy - i've gotten up the nerve to put her in the ground! i think you're right, with how large it already is, i'd need a huge pot. now i've got to figure out where to plant it so that it's not getting too much water. where i WANT to put it, where it'd be the prettiest in the yard, is where i have some impatiens, zinnias, and coleus, and they are heavy feeders.

thanks again!

angela

I'm not sure if I'm too late to chime in but I have never had good luck transplanting dahlias. They tend to do just fine in the pot they're in but will wilt and react terribly to being transplanted. If you want to put it in the ground, just dig a hole as big as the pot and a little deeper, and drop the whole pot in. Cut back some of the side stems for better air flow and then cover the rim of the pot with dirt -- you'll never know the difference. You will have to take it out at the end of the season but it's the only way I've ever had a potted dahlia become a planted dahlia. Also, I would avoid Miracle Gro -- the nitrogen content is way too high for dahlias and you will get weak stems and small blooms. Try a fertilizer with a low first number and higher second numbers (nitrogen/phosporus/potassium). If I'm too late, I hope I'm wrong! Good luck!

@pvdahlia - thanks for chiming in, i want as much advice, info, suggestions, and recommendations! i do stay away from MG and only use tomato food. i've gone ahead and planted it, and i'm keeping my fingers crossed!

thanks again :)

Ladybugsmom did you plant just the plant, or the whole pot?

I've transplanted 3 foot plants from the garden to another spot in another bed, but never out of a pot, so I'm curious what you decided to do and how it went.