Sowing dahlias step by step: from seed to flower

Of most dahlias, you put a tuber in the ground to be sure to see that particular variety bloom. This is because tubers are always true to type. That means that, even if you take cuttings from them, they always produce the same variety. But did you know that you can also sow dahlias? It is fantastic to sow them in March and see them bloom for the first time that same summer. What makes sowing so special is that you are never sure what you will end up seeing. This is because each seed contains a different gene and is therefore unique. Through cross-pollination, it is impossible to get the same flower as the mother plant. It's like entering the lottery. And I love that. There's something magical about it, not knowing what's coming. At the beginning of summer, I look at the flowers from their buds. Not all seedlings of dahlias are equally special, but they are always unique and so theoretically do not exist yet. 

New varieties are created by manual or natural cross-pollination. So every variety on the market today was once a seed. Quite extraordinary, right? Through intensive selection at growers (dahlias often have to meet a lot of requirements) gems are discovered. Only when a new variety remains stable for years is it introduced and you can plant it in your garden.

There are two different ways to do cross-pollination. Either you let Mother Nature do her work, and let pollinators do the work, or you do the pollination manually - by hand, that is. If you are just starting out with dahlias, it is much easier to let nature do her work. All you have to do is let some dahlias bloom and you're done. With manual pollination, you are going to select 2 parent plants and then screen them off with netting so that bees cannot reach the pollen. You then often have to remove the top petals to see the pollen. At the ideal time, preferably around noon, bring the two dahlias together and rub them together. Very exciting it is not, this somewhat forced fussing with dahlias, but it assures you of the right characteristics. 

Chances are very good that after sowing dahlias you will see open flowers. The true pompon, ball and giant dinnerplate dahlias are often more challenging. Since our plants are now often intermingled and there is plenty of cross-pollination, it is more likely that you will get open types. And you shouldn't be sad about that, because bees, bumblebees and butterflies love that kind of flower. The open center means there's plenty of pollen and nectar available, and that's exactly what those faithful allies in the garden are looking for. The more open dahlias, the more there is to eat. Because although I find those thick flowers of dahlias incredibly beautiful, it is the so-called single or open flowers that make my heart beat a little faster. The variety, the colors and the incessant visit of all that floats and flies in the garden: every summer and fall I bounce with enthusiasm. The single dahlias are ideal garden plants, but somewhat less suitable for keeping in a vase. This is because they wilt more quickly due to the lack of many petals. Therefore, combine them both in the garden, then you will have enough dahlias to pick and keep the bees, bumblebees and butterflies happy at the same time. 

Dahlias produce dark brown to sometimes black seeds. They are fairly flat with a small thickening at the back. Each seed has the potential to become a large plant with hefty tubers and unique flowers. Dahlias can be sown from late March and early April. Do not start too early, as dahlia seedlings are known to grow quickly.

It takes on average 1 week for the seeds to germinate and another week to a week and a half before the first real leaves appear. By then, quite a few roots have already formed and you can give each plug its own pot. P9 pots are very suitable. I use peat-free potting soil at that stage to keep the seedlings growing until they can be put in the ground in May. Seedlings of dahlias grow very quickly and take only 4 to 6 weeks to evolve from seed to plant. Keep in mind that they are frost sensitive and, like the tubers, cannot tolerate frost.

Otherwise, the process is similar to that of pre-drawn dahlias. Plant in the ground, about 30 to 40 inches apart, water vigorously, mulch and done. Feel free to also add some well-digested farmyard manure or lava meal to the planting hole, which will help the plant grow. You could, in theory, plant seedlings much closer together. This is mainly what breeders do, because they have hundreds, if not thousands, of seedlings hoping to select a few promising ones. Because make no mistake: not every seedling makes it in the end. Strict selections precede it. Usually one selects on color, shape, firmness of flower stems, closed hearts and so on. In this case, most breeders apply the principle of "kill your darlings." It is impossible to keep them all over. But let's face it, that we hobbyists want to enjoy them more than anything else. It does not always matter whether a flower produces completely closed hearts, or forms large stems, because they would do better in bouquets. It is the run-up to the first flower unfolding, the process from seed to flower, that makes it interesting and very captivating. It's pure magic when you consider that after 1 season, because I guess I didn't tell you that yet, you already get to see flowers. I put seeds in the ground in the spring with the intention of being surprised by what color or shape the dahlia will eventually be. It feels a bit like entering the lottery every year. With the exception that in this game you always have a prize, of course.