Expert: Kenneth Joergensen - 3/2/2004

Question
Hello,
I planted dahlias in a pot about 2-3 weeks ago. I was wondering when it will bloom? I am not sure of my USDA Gardening Zone, my state is GA my zip code is 30165. Here lately the tempature has been rising but there is not much sun though. I have kept the pot indoors on a window sill which gets the most if any sun. Is there anything I can do to speed up the process of growth? Should I put it outside when the weather is nice or should I keep it indoors? I have never had a indoor plant before.
Thanks,

Answer
Usually Dahlias flower midsummer from a spring planting. It takes about 8-10 weeks from planting of the tuber to flower bud formation and another 3 weeks for the buds to open. If you pinch out the growing tip (to get bushier plants with more flowers) the flowering time may be delayed by another 3-6 weeks depending on when you pinched. Count on roughly 3 months from planting of the tuber until flowering. 4 months if you are growing from seed.

Keep the dahlia in a very sunny window and rotate the plant daily so it grows straight instead of towards the light. Dahlias are high light plants and require lots of sun. If you do not have a very sunny window, it is recommended to put it outdoors as soon as last chance of frost has passed. It needs lots of sun to flower properly.

Fertilize the dahlia weekly. If you buy a package of 15-30-15 miracle grow, fertilize the dahlia with 1 tsp per gallon of water every week (see back of lable for more information). You can also use OSCMOTE 14-14-14 (or NUTRICOTE 14-14-16) instead which will feed it for 3 months (no need to fertilize weekly then).

I don't know when you started the plant .. if it was started from seed, tuber or purchased as a potted plant. If purchased as a potted plant, it may have undergone several weeks of growth already and will probably flower within weeks, subject to sunlight and fertilizer being adequate. If you started from tubers or seed, I would pinch out the growing point when it is 6" tall (pinch off the top 2 set of leaves), but that is not required if you bought it potted.