Where / When / How to Plant Dahlias

Growing dahlias requires some thought and care but is quite straightforward...and extremely gratifying!

It all begins with a dahlia tuber which often resembles a small sweet potato- with a body, neck, and bit of the old stalk where an eye has formed (or soon will).

WHERE Can I Plant Dahlias?

Ideally, dahlia tubers should be planted in well-drained soil which is rich in organic matter in a location receiving 6-8 hours (or more) of sunshine per day.

Most gardens containing soil that has been amended over time will be more than adequate but it is important that the area is not heavily shaded. Dahlias receiving inadequate sun will not thrive...and may not even bloom.

Dahlias also prefer a slightly acidic soil but in our experience they can tolerate mildly alkaline soil as well.  Ours pH is 7.0-7.4 and although we would prefer a more acidic soil our dahlias seem to do fine.

For space-challenged gardeners, growing dahlias in containers may be the only option. We've done this on a small scale and the results are surprisingly good - but requires significant attention to soil moisture and plant staking / support.

WHEN Can I Plant My Tubers?

Dahlias are frost-sensitive plants and their tubers are prone to damage or loss if subjected to freezing temperatures. Although we are mindful of the frost-free date in our planting zone, we are never in a hurry to get our tubers in the ground. They only grow well in soil that has begun to warm.

As a rule-of-thumb, we plant tubers after the threat of freezing temperatures has passed and the soil is about 60°F or warmer.

HOW Do I Plant Tubers?

We plant tubers about 4" beneath the soil surface laying horizontally (on their side) with the eye facing up toward the surface.  When planting multiple tubers we space them out 18-24". Although we've grown them as close as 14" to each other, in our experience they do noticeably better when given a bit more room - and the extra flowers they yield when they're happy more than compensates you for the extra space!

In our case, we plant tubers in 3' wide beds that are 100' long - and we plant in two rows in each of these beds. To suppress weeds we use chipped leaves collected during the previous fall. At the end of the growing season these get tilled into our soil. If we run out of leaves before we've mulched all our beds we use fresh grass clippings.

In spite of our best efforts, some weeds always find a way to grow. We never use weed-killer sprays which can damage or kill our tender plants. Instead, we manually weed our beds which, we have found, is easiest after a rainfall.

You may notice that different growers use different techniques for planting, growing and maintaining their plants. Experience (and experimentation) will prove the best guide to managing your own dahlia patch.