I have had very good results from growing dahlias from tubers for quite a few years now. Then, this year, when I was ordering tubers from a new source, I saw they had seeds for sale. I had seen the smaller, bedding dahlias for sale in garden nurseries in the past, but had never purchased any. Now, I thought this was a cost effective way to grow my own. Only they didn’t end up being little dahlias.
Following the directions on the seed packet and my own basic seed starting procedures, seed germination was about 50 percent. The first sprouts took a few days to show up, but others emerged sporadically over another few days. They were all in the same tray, getting the same amount of moisture and heat, so there is nothing I can pinpoint as causing this. They even showed up in random pots around the tray. (click on any photo to enlarge)
Once they had sprouted, they were quite easy to take care of. The first leaves were large enough as to not be fragile or easily lost. I did take the basic plastic bag off of the tray after about 3 days, so I had to water lightly and regularly to get germination of the stragglers.
After hardening them off, like the rest of my spring seedlings, I decided to plant them around my pepper plants, which were growing vigorously, centered in a 12 by 4 raised bed. The dahlias had healthy roots and didn’t seem to be stressed out at all by transplanting. Then, I waited for the blooms.
And I waited and waited. It wasn’t that the plants weren’t flourishing. Neither was I over fertilizing, which can inhibit flower production in some plants. What was happening is that the plants were getting quite large. In fact, they were getting larger than the mature pepper plants. This was not what I had expected. I went back to check the seed packet, but didn’t see anything about size of plants.
In August, I finally started seeing some fat buds. At this point, the dahlia plants and buds look just like all the ones that I have planted from tubers, only not as far along in their seasonal growth. Then, in the beginning of September I had a blossom!
The seed packet had made it clear that the blossoms would not be as fancy as the ones grown from tubers. And they could not predict which kinds of blooms I would get. The blooms were indeed single blooms, meaning one layer of petals, much like multi-colored sunflowers. They are not as showy as my beds of tuber started dahlias, but they are not weedy looking either.
There are still a few plants that haven’t bloomed at all yet. Cool fall temperatures are now the norm and an early frost could happen any time. I am planning to dig them up after a frost, supposing that there will also be tubers. If so, I will do my best to save them over the winter and get them off to an earlier start next spring, like I do my other dahlias.