Dahlia tuber storage
Keeping your dahlia tubers healthy until spring requires some extra care in our dry Alberta winters. I store mine each year for roughly 6 months and have learned what works best in our climate. You can improve storage success rate with how you treat your tubers before they go into storage as well. I take the following steps each fall to keep my tubers in great shape for the next year:
1) In the last month before an expected frost, I reduce the watering and fertilizing gradually and then stop completely. This helps the tubers firm up and be less prone to rot during storage.
2) After the plants have died or been cut down, I leave the tubers undisturbed in the ground for a week to develop eyes. This makes it easier to divide the clumps.
3) When lifting tubers, we keep the clump intact. I never wash my tubers, it is unnecessary for me as my soil is loose and falls off the tubers. I let the clumps dry in a warm place for 24-48 hours before packing away. If dividing is necessary, I do it just before packing.
4) Tubers must be kept at a cold, but not freezing temperature to keep them dormant. I store mine in my heated garage which stays at about 5C even during the coldest parts of winter. A cold storage room in your house could work as well, as long as temperatures stay between 5C and 10C. Do not let your tubers freeze or they will rot.
5) I pack my tubers with spruce shavings in Rubbermaid totes. The totes have holes for ventilation and lids. I layer shavings and tubers until the bin is full, making sure all the tubers are covered and not exposed to the air. Any tubers that aren’t covered will dry out and may not be viable in spring. Spruce shavings are my favorite medium for storing because it’s a renewable resource, absorbs any moisture the tubers give off and in the spring when we’re done with it, we reuse it as chicken bedding. We find it in big bales at our local feed store at a very reasonable price.
6) Each tuber clump is labeled with a tag showing it’s variety and then I record the contents of each bin in a notebook. Bins are numbered so I know the exact number and kind of tuber in each one. This is an extra step to prevent a huge amount of “mystery” tubers from creeping into my inventory.
7) We stack the full totes on shelves off the floor of the garage to prevent them from getting too warm or too cold. I check on them occasionally throughout the winter. I open the lid, move the shavings and feel the tubers for signs of desiccation or rot. If the shavings seem quite damp, I’ll leave the lid ajar for a day to lower the moisture level. If I see tubers starting to sprout, I know the temps are too warm and will make sure our in floor heating hasn’t been set too high accidentally.
8) By April when outdoor temperatures start to rise, tubers naturally start to sprout. This is when you can remove your tubers from storage and pot them up to get them growing indoors before transplanting outside. Once the risk of frost is gone, tubers can also be planted directly in the ground. This is how I grow my dahlias, planting the tubers directly in the ground without potting up. I typically have blooms 8 weeks after planting sprouted tubers in the ground, with full production by 10 weeks after planting.