Waking up your dahlias
After a long winter in storage, it’s time to pull those dahlias from their slumber and get them ready to go into your garden. I always start this process around the end of April , to give my dahlias about 4 weeks to wake up and start sprouting before I plant them into the garden the first week of June. I know it is tempting to start digging in the garden as soon as the ground is workable, but where dahlias are concerned, later is better. They dislike cold, wet ground and rather than getting a head start as you might hope, your tubers may just rot in the ground. I have learned to wait until the soil is warmed up and the risk of frost is minimal, which is usually the first week of June here in Zone 3a. Dahlias are tender like tomatoes and will be damaged by the slightest frost but if you want to get a head start indoors, there are things you can do. Here’s how I get my tubers growing:
I open my lidded totes filled with spruce shavings and remove my clumps or single tubers, being careful not to snap off any shoots that have started growing while in storage. These shoots are the future stems that will produce your flowers. If you do accidentally snap off a shoot, save it and set it in a glass of water in a sunny window and it will root. Then you can pot it up for another dahlia to plant outside.
I take the clumps of tubers from their storage totes and place them in trays ( I use my 1020 seeding trays but you can use aluminum roasting trays, small plastic bins or anything that will hold moisture. I lay the varieties together in trays and partially cover them with the spruce shavings from their storage tote. You can also use vermiculite or potting mix, or a combination.
I check the moisture level of the spruce shavings and if it seems quite dry, I sprinkle the tray with water so the dahlias will have a moist, but not wet environment to stimulate growth. Tuber are prone to rot remember, so you don’t want them sitting in wet material in their trays.
I place the trays in a warm, sunny location like a south facing window, a greenhouse or cold frame. The warmth and sun will tell the tuber it’s time to start growing. Do NOT leave tubers outside at night if there is any risk of frost. If you are putting them in a cold frame or unheated greenhouse, make sure you bring them in at night so you don’t lose your tubers to frost.
Check your trays daily for moisture levels and sprinkle them with a watering can to keep them moist. Your tubers will shrivel and desiccate if you don’t provide enough moisture.
In about ten days to two weeks, you should start seeing little shoots forming at the neck of your tuber. If not, don’t panic. Some tubers take longer to “eye up”. I’ve waited a month and just as I was about to toss the tuber, I spy green!
Once your tubers have shoots, make sure they receive strong, adequate light, just like seedlings need. Without it, your dahlias will grow tall and spindly and suffer transplant shock when placed in the garden.
Now the hard part, being patient while the weather slowly improves and summer arrives. I’ll share how I plant my dahlias and care for them in the garden next time.