Dahlias, Winter Storage for Summer Splendour

Sunday, October 05, 2008 04:50 AM

If you grew Dahlias over the summer you can save the tubers and re-plant them again next spring to have beautiful flowers for the summer.

Dahlias are grown mostly from tubers which are planted in the spring, so that they can bloom throughout the summer. They are very touchy for frost and tend to be one of the first plants that get killed by the first fall frost when temperatures dip below -1 Celsius. The foliage of the dahlia plant becomes blackened and limp when it has been touched by frost so it is easy to tell. Once this has happened you should cut the stems back to within 6 inches from ground level. The next thing you want to do is loosen the soil around the tuber by getting a gardening fork and carefully dig around the tuber, but not getting too close as you do not want to damage the tuber. After you have loosened the soil around the tuber dig it up and gently shake off any extra soil from the tuber. You will notice that the plant likely produced more tubers that are all attached to the main stem. Try and keep them all intact for now.

You want the moisture to drain from the neck of the stem so place the tuber upside down for a few weeks in an area which does not go below freezing and is airy. When the neck of the stem is really dry, the tuber is ready to store, so sprinkle some bulb dust over the tuber which will aid in the prevention of fungus or insects from harming the tuber. Then place the treated tuber in a container or bag filled with vermiculite, dry sand, or peat moss. Label the container with the variety name, color, and height so that next spring you will know what it is. Store the container where the temperatures are 5-8 Celsius. Every few weeks check the tuber to see if they are still healthy, and if you see any rot on the tuber cut off the bad part and treat the healthy part of the tuber with sulfur so that the rot does not spread any further. You also want to make sure that the tuber does not shrivel and dry out. If it becomes too dry, remove it from the storage container, give it a slight mist of water and replace it back into storage. In the spring around March split the tubers from the stem by cutting them with a sharp knife and leaving a small portion of the stem on the tuber. Make sure that each tuber has an eye as this is where the new plant will form.

Plant each tuber into individual pots that are filled with a good quality potting soil. Plant the tuber by holding it by the stem end up in the center of the pot. Fill in the soil around the tuber so that the top of the tuber is even with the soil when it is finished being planted. Give it a good soaking of water and then place it in a warm sunny location. Before the tuber starts to grow you want to be careful when watering, only giving it water when the soil becomes slightly dry. After you begin to see growth, increase on the water a little bit and fertilize with 10-52-10 a plant start fertilizer. When the plant has established itself, switch to an all purpose fertilizer 20-20-20 for all around growth.

To keep the plant even, and well rounded rotate it every few days so that each side of the plant gets even exposure to the sun, and pinch out the center of each stem once it has three leaves as this wall cause it to produce side shoots. By the beginning of May you will want to start hardening off the plant by putting it outdoors during the day and bringing it indoors at night. By hardening off the plant it will be ready to go outdoors at the end of May (when all threat of frost has passed) and will not be stressed. For optimum flowers, fertilize with a flowering plant fertilizer such as 12-36-12. Dahlias prefer sun so place the plant where it will receive lots of sun. Smaller varieties can be grown in containers and be placed on the patio and larger varieties can be transplanted into the flower beds. Throughout the summer continue to fertilize and remove the dead flowers as they appear so that you will get lots of flowers throughout the summer.

-Jos

Jos Van Hage owns and operates two Art Knapp Garden centres in Prince George:

Highway16 west at Kimball road
Highway 97 North at Northwood Pulpmill road

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Dahlias, Winter Storage for Summer Splendour

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