Wintering Dahlias #1

Stan - We have dahlia that we have stored in the basement every winter for 2 years in a brown bag and replanted indoors in March/April before replanting outside . When is the optimal time to cut back and store ?, as the root system seems to be doubling, can we split it and obtain other plants ? When to take out geraniums and how best to make them winterise ?

Marc,
Edmonton

Marc - Maintenance of dahlias begins now. Dig the tubers with as much soil that clings to the root systems. Lay them out to partially dry the soil, then lay them with foliage up, and the tubers on, into cardboard or wood boxes, cover with dry peat moss up to the necks where the stems begin. Keep them outside to continue their ripening. Bring them in when day temps are below freezing. Store in bags or leave in the box. By Feb. Mar. they will begin to sprout. Take them and cut off the last years growth and pot into individual 2 liter milk containers. Cut drain holes in the side near the bottoms. They will continue to grow until planted outside. If excess growth begins to become long and weak, cut back half the length, and move to more light with cooler temps.

Wintering Dahlias #2

Hello Stan.

I volunteer in a botanic garden. We built an 8x8 coldroom last fall and store more than 100 dahlia bulbs in boxes and brown paper bags. The temperature up till now has been between 2 and 4.5 C, which is accomplished by changing light bulbs [100- 150 or 200 watt] depending on the outside temperature. The boxes are covered with black plastic to keep the goods in the dark. Today I noticed a fair amount of rotting on several clumps. I tried to clean them off as well as I could but am not sure what will happen from here on. Should I place a small fan inside for circulation? Some of the cardboard boxes were getting a bit moldy. Is there a powder I can use to protect the bulbs? I hate to lose all these beautiful flowers. Your expert advice is really appreciated.

Sincerely
Chris

Chris - Dormancy is not death. Dormancy of a plant means a rest period that equates to the hibernation of bears or badgers.

Your dahlia problem stems from the lack of air circulation, that covering the tubers with this product, has the effect of suffocation. Because the tubers are still an organ of a plant that is in low metabolism, a modicum of light must be supplied either by natural sources, or by a electrical 10 to 20 watt bulb.

Take all the tubers out of the boxes and dust with Potatoe and Tomatoe Dust, a product by the Greenleaf People, and available in all the garden stores. If you have sulphur dust or Benomyl dust, use it.

Lay the tubers out in a cool darkened place to dry, then re- store into shavings, sawdust or coarse peat moss, all supplying the needed air circulation while still in the media.
Hope you pull this off.