Expert: Kenneth Joergensen - 10/18/2004

Question
Hello, I live in Olympia, WA and want to grow dahlias that will have blooms by July 15 when our son's wedding will take place,  Shadow Cat is the dahlia chosen.  Can we start these tubers in the garage in Jan, Feb, or earlier and how do we go about that?  Should we use grow lights?  Thank you so much!  Karen

Answer
It usually takes 3-4 months for tubers to bloom.

Dahlias usually go through various flushes of bloom and you can of course risk that on July 15th, the plant is between cycles. It is very hard to time flowering as it depends on temperatures, sunlight, etc. If you have more tubers, hopefully some if not all will be in flower.

If you plant them indoors march 1st, you should have flowers by July 15th (of course no guarantee).

If you start them, note that temperatures around 65-75 gives faster growth. You would need grow lights. A 'shoplight' (double fluorescent light bulbs) suspended 2-3" above the tops (adjust as growth takes place) is your best bet.

shoplights costs $7-15 for a 4' long fixture (home depot for example). It takes 2 x 48" long light bulbs. I recommend the regular "cool white" bulbs (e.g. as opposed to buying plant grow bulbs, or buying kitchen/bad - warm - light bulbs). Not only are the cheaper.. they are better too.

When dahlias plants are 8"-12" tall and have 2-3 sets of leaves, pinch out the top set of leaves so that the plants stay more compact, and branch better.