I may have used this headline before, but it is just so appropriate. In most of North America the soil is warm enough to plant. In zones 1-3 it may be iffy until the end of the month. Most of the dahlias I will plant out are either in pots or small trays. They have shoots of varying heights and root growth. That will give them a good start.
I will put them outside in the shade for a few days before planting in order to acclimate them. I bury the tubers between three to four inches below ground level. Some experts recommend six inches measuring from the top of the tuber as it lays sideways. If the shoot has a pair of green leaves do not bury the leaves or the plant may rot. Leave a little depression of soil and fill it in as the plant grows.
As you have read, I like to do things the easy way. This year I have encountered a mystery. A few tubers have shown a black dot on the shoulder that usually develops into a shoot and ultimately a plant. Unfortunately the dots did not develop, and the tuber did not develop roots after 6 weeks. They just sat there. I have a suspicion that these tubers, if planted out will not grow, notwithstanding the tiny eye. I have asked the question in the chat rooms, and the best answer I received was “dahlias will be dahlias.” I will put all these tubers in a bag with moist vermiculite and see what happens. One of my dahlia heroes, the late Gordie Leroux, told me once that If a tuber does not eye, cut off a piece from the end of the tuber, and bounce it against the table three times. Who knows?
Regular dahlias need a stake. Set it before you plant, or you may decapitate the plant. If you care to know the bloom's name, put a tag on the stake. Hardware or plant stores have a variety of tags. Use a permanent marking pen and perhaps make a note, just in case. Or use a tape labeling machine (about $35). My friends say the tags can be reused season after season, just be sure to get the "outside" tape.
See the YouTube links below that will show how to plant dahlias.
Most of all, have fun!
Harry Rissetto.
