American Dahlia Society

News from ADS!

Planting Time

For gardeners every year is an adventure.  

Land of Enchantment - photo by Diane Kalb
Winner 2nd place, Class 4, ADS 2019 Photo Contest

The last frost date is the time to think about planting tender garden flowers, including dahlias. In 2020 Jack Frost has been playing hide and seek. It is mid-May and we are still edging toward a nightly frost here in Virginia. To see historic averages for your area consult the internet, for example this US Climate Normals page.

Other planting considerations are soil temperature and moisture. If there is good drainage, shoot for a soil temperature of 55ยบ F. Soggy soils will be a challenge to the tuber's root formation, so wait until the soil is a bit warmer. This also applies to tomatoes and basil. If you have a kitchen thermometer with a probe, put the tip into the soil about four inches deep to test the temperature. Soil thermometers are available at most garden shops and on-line. 

Generally speaking, dahlia culture is similar to growing tomatoes. The plant will ordinarily grow taller than four feet by September, so for dahlias other than the short container or patio types, you will need to stake (or otherwise support) your dahlia plants at planting time. Like tomatoes they thrive on 5 to 7 hours of sunlight. If you want to preserve the name of the dahlia, put a tag with the name on the stake. I have friends that tag snowdrops and daffodils. It is up to you. Although a name tag always impresses visitors.

If the dahlia comes in a pot, plant it at soil level and treat it like the other plants in your garden. If you are planting a tuber, plant it flat, with the top of the tuber about three inches below the surface. You do not want the shoot to have to work hard to find the light. There is no need to water the tuber right away. The shoot can draw moisture from the tuber and the young roots.

The internet is filled with instructions for planting dahlias. We have noted some sources, below. 

Several of the dahlias that I grew last season were left in the ground. A number of them have put up healthy shoots because we had a relatively mild winter in Northern Virginia.  This goes to show that planting a dahlia is pretty simple. Put the tuber in the ground, cover it up, and it will grow.

Have a great 2020 dahlia season,
Harry Rissetto

Sources for more information:

Dahlia University - this feature on the ADS website offers short "classes" and videos on dahlia growing and more

Video:  Planting Dahlias

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