This year, for fun, we are encouraging our members to grow dahlias from seed to see what flowers they might get. In September, we will have an informal flower show where members can show off their favourite blooms (judging will be by popular choice, ie what people like just by looking, and not by ADS judging standards.) Members will vote for their favourite bloom and one will be awarded “The People’s Choice”!
But before all that, we will need to get our seeds growing! Let’s start with soil. Many people make their own soil combinations and they can contain perlite, vermiculite, washed sand, spaghnum moss, peat moss, in addition to potting soil. Different combinations of these (and maybe other additions not listed here) can be created depending on what you like to grow. For starting dahlia seeds, a combination of peat, perlite and vermiculite is recommended and the process is not unlike starting vegetables indoors.
Fill your seed starter pots with your potting mix. Pour boiling water slowly over the mix (be careful of steam!) and let sit 10-15 minutes to cool. What the boiling water does is to help kill off any molds or fungus that create “damping off”. You don’t want to lose any seedlings to damping off. You could also use something like “Damp-Aid” to protect your seeds, and you can make something similar out of ground cinnamon and ground cloves. All you need to do is dust your seeds with it before planting.
Plant your seeds! I’m a fan of what is unglamorously called, “The Plastic Baggie Method”: put your pots in a plastic bag. Yep, it’s that simple. The small Ziplock Freezer bags work perfectly for my 2.5″ square pots, but use whatever size will cover your pots. Now you will need light and warmth. You could place your sealed baggie in a warm, sunny window or under grow lights; either way is fine. Check on them every so often to see if any have sprouted.
Once your seeds have sprouted, leave them in the plastic bag until there are at least two sets of “true” leaves, and then remove the plastic bag. Keep seedlings out of direct sun but in bright light at first, and keep well-watered (but not soggy). Pot them up as needed.
When it is time to plant your baby dahlias in the garden, or outdoor containers, first harden them off for a few days by gradually exposing them to cooler outdoor temperatures. The best type of day to plant seedlings is an overcast or rainy day, towards the end of the day. This helps the dahlia seedling to cope with the shock of being planted without having the sun beating down on it as well.
And that is it! Easy. I’m really looking forward to the informal show in September to see what people will have and what the variety of blooms will be like.