Dahlias are one of those magical plants that go in the ground as one and come out as many. So you will always have a multiplying supply of tubers to plant. There’s a long list of chores in the Autumn, and digging and storing the dahlias is high up on that list. The first time attempting to store my tubers, I wound up with a squishy, shriveled-up tuber with no eyes to sprout for the next year. It was a major disappointment. I like things to be as easy as possible but also organized enough that next year isn’t a bloody mess.
Dahlias are such a beautiful flower but with that beauty comes a price. Tubers aren’t cheap so it's devastating when the tubers you stored all winter are untucked in the spring only to find they dehydrated completely or were stored where the moisture was too high and they have rot. This post will help you to understand how to properly store to ensure you are able to keep and multiply your tubers year after year, saving you money and increasing your yields, year over year. Proper digging, separating, labeling, and winter storage will keep your garden exploding with beautiful petals all summer long.
Unless you are in zone 8 or higher at the end of your gardening season, it’s almost time to dig up your dahlia tubers if you want to save them to grow again next year. The best time to do this to ensure the tubers have reached maximum growth potential is after your first frost. The first frost will affect the tops of your dahlias, killing or damaging any flowers and foliage, but your tubers will be okay tucked beneath the ground as long as the temperatures of your soil stay above freezing. However, you should definitely ensure you dig up your tubers before the ground freezes, or you will lose your tubers. Waiting until the first frost ensures your tubers have had enough time to grow to maturity, improving your chances of storing a healthy tuber to be planted again next spring. Harvesting early could result in an under-mature tuber, resulting in poor winter storage and an unlikelihood of the tuber being viable to plant.
Digging Process:
Tools
Shovel/Pitch Fork
Crate/cardboard box
Snips
Painters Tape & Sharpie for labeling
Cardboard box/milk crate/paper bag to store in
When it's time to dig your tubers, I like to leave the tops of the plant intact with a flower or two on them so I know what variety I am digging. One of the most important parts of digging your dahlias is properly labeling them. There is nothing worse than planting the wrong variety in the wrong spot and finding out after it's too late. I also like leaving the tops on until I have dug up my tubers so I can see better where the plant was aiding in knowing where to dig.
Begin by inserting your pitchfork wider and deeper than your plant, being careful to avoid any tubers. Lifting your fork, you can hold the base of your plant to help gently remove the clump of tubers from the ground. Remove as much loose soil as you can with your hands and fork gently, being careful not to break off or damage any tubers. Important note: a viable tuber must have part of the crown of the plant still attached for it to produce the following year. The crown is where the tuber begins to grow from the neck of the plant. Any tuber that fall and break away from your clump can be discarded if it does not have part of the crown attached. If you are unsure you can store with your clump of tubers and wait until the spring to see if it sprouts. I will have another post on bringing your tubers to life after winter, separating and planting coming.
Now that your tubers are out of the ground, this is the most important part of the whole process. DO NOT WASH YOUR TUBERS. I have never had any luck washing my tubers off before storage. I like to think of soil remaining on them as a protective coating keeping them from shriveling up over the winter; it acts as a barrier. Finally, I leave my tubers as a whole clump; I don’t separate each individual tuber prior to storage. I think this step would be beneficial to someone looking to sell or give away tubers, but as a home gardener, I find it unnecessary, and anyway I can make my life easier and streamline I will take it.
I like to use painter's tape at this point to label the main stalk of my tubers. Labeling is so important; I always label the stalk of the tuber clump as well as the box/bag with the variety because it is so easy to mix up if you have multiple varieties.
Storage Options:
Key points to remember:
Tubers should be stored between 3-10 degrees Celsius.
-Temperatures lower could cause your tuber to freeze and then rot.
-Temperatures higher may send your tuber into a forced sprouting situation where your tuber thinks it's springtime and should begin sprouting.
Humidity levels should be 75-85%.
-Too high of a humidity level and your tubers run the risk of rotting.
-Too low and your tuber will dry out.
Airflow:
Your tubers like to breathe a little, avoiding using airtight containers to store your tubers.
When ready to store your dug-up tubers, there are a few options to choose from; however, the two that have worked best for me are using an old milk crate and paper grocery bags or a cardboard box (do not tape shut for airflow purposes) and newspaper.Both options provide ample airflow; your tubers like to breathe a little and prefer not to be in airtight containers such as a rubber-made tote, for example. Mark the box and/or bag with the variety you are storing.
Keeping our key points in mind, where we keep our tubers is important. They should not be kept outdoors where temperatures can drop below zero. Store your tubers in a cool, dark location. An unheated basement, crawlspace, or garage is a great space. Tip (keep off of concrete floors as they tend to draw moisture from your tubers if left on the floor, keep on a shelf if leaving in the garage or a concrete basement floor)
Monitoring:
It’s good to check on your tubers throughout the winter months to see how they are doing so you can make adjustments to the environment if needed. Check for signs of decay, rot, pests, or dehydration. Making small adjustments like spritzing your tubers if they appear too dry or adding a dehumidifier if the humidity levels have risen too high and you are worried about rot if you notice they aren’t storing as well as they could.
When I first stored dahlia tubers many years ago and I went to pull them out in the Spring and found a box of very shriveled-up tubers, the disappointment was real. But hopefully with this guide, it will help you to understand what your tubers need to be properly stored over winter. While gardening is a very personal and environment-based hobby, everyone does things a little differently based on the circumstances. Hopefully next spring you’ll have a box of nice, plump healthy tubers to plant for a garden full of beautiful blooms all summer long. I’d love to hear from you with any tips you have learned along the way for storing dahlias.
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