After the first night frost it's time to set your dahlias safe for the real winter. Dahlia tubers hate frost, they will freeze and die. If it's too wet in the ground, they can also rot. So if you want to enjoy your dahlias again next year, take the following steps:
- Wait to take out the tubers until a few days after the first night frost. The plant will then blacken and die and give all its energy to the tuber, then the tubers are full of nutrition and have the best chance of surviving during winter storage.
- Watch for foliage to die back after the first killing frost in autumn. Trim the dead darkened foliage to 10 cm (3 inches) above the ground.
- Write name tags and adjust them to the stem. Use a plastic label or a solid paper that you attach with a pinch. I immediately write the color on it and whether they are tall, medium or short. This way you can easily get started with planting next year.
- Loosen the soil around the dahlia tubers by trusting the prongs of a pitchfork into the ground about 30 centimers (one foot) all around the perimeter of the plant. Prying up on the pitchfork should free the tuber from the soil.
- Allow the tubers to dry for a few days. Store the tubers in a basket, paper bag or cardboard box filled with moist sand, sawdust, peat moss or vermiculite. Never store the tubers in plastic, as they will rot.
- Give them a cool, dry and frost-free place eg in the barn where temperatures are consistently between 4-10 degrees (40 and 50 F).
It takes some work, but next year you will be rewarded with rich blooming dahlias again.
If you find it really too much work, you can take the risk of leaving them in the ground. In a winter that is not too cold and depending on the place and the soil, they will survive. Give them an extra layer of compost as a warm blanket. If the winter was really too hard, just order fresh new tubers from our dahlia candy shop.