Expert: Long Island Gardener - 6/21/2007

Question
I bought bulbs this spring from park seed and a local garden center, they sprouted to 6"-8" and then stopped growing. i planted them in potting soil in large containers. I started them indoors in late April and moved them outdoors mid May after the last frost. Why have they stopped growing?

Answer
Dahlias need warmth and light to grow.  If they're still alive, they must be doing something.  Do you see roots?  Are they healthy -- the tubers should be firm.

When your Dahlias get to a foot tall, cut off the top growth to encourage branching.  You'll multiply your flowers that way.

Don't forget to stake.  You'll be glad you did when they start to take off.  This is not something you want to do later.  Get the stakes in the ground.  You'll need large, thick stakes.

A dose of Bone Meal in the soil with them would encourage strong roots and big flowers.  If you did not fertilize, you should pick up a container of high Phosphorous fertilizer asap and dose your Dahlias with it.  These plants MUST have a full dose of Summer Sun to do well.  Make sure they're not sitting in the shade.  Sun Sun Sun.

Check the roots, fertilize, and get back to me.  Thanks for writing.