The dahlia is a beautiful flower, but keeping it can sometimes cause headaches. If this is your first time growing dahlias, you should know that you must remove the tubers from the ground in the fall since they cannot withstand frost. If you don't want to bother with that, you can always dig them up and bake yourself an excellent dahlia cake.

If you want to multiply your tubers, here are some tips to help you with winter storage.

Identification of tubers

First of all, you must clearly identify your tubers before storage since they all look the same in the end. We identify them using a permanent marker directly on the tuber, so we are sure not to mix them together. If you have several tubers of the same variety, you can only identify the container or place an identification stick inside.

Control temperature and humidity

The ideal temperature for storing tubers is between 4°C and 10°C (40-50°F). What is more difficult to maintain is the humidity of the room: it should not be too humid as to cause mold nor too dry as to not dry out the tubers. If you have a garage that you heat to a minimum or a cold room, this is practically ideal if not the coolest place in the house. Unheated garages and sheds should be avoided due to the risk of freezing.

Container for storage

Almost any container can be suitable for storage: a cardboard box, a wooden box or plastic bins. If you use the plastic bins, be sure to poke a few holes in the lid to allow air to circulate.

What should I store my tubers with?

You will need to use different materials to "insulate" your tubers while maintaining a certain air circulation so that they remain intact.

Horticultural vermiculite

Horticultural vermiculite (coarse grain) can absorb excess moisture without drying out the tuber and allows air circulation in the container. This product is expensive and it is best to wear a mask when handling it. Construction vermiculite should be avoided since the small grains and dust can cause your tubers to rot.

Peat moss

Peat moss (also called Peat Moss) gives good results and is not too expensive. On the other hand, you must pay attention to its humidity level. It may be too wet if the bag has been punctured. If this is the case, do not hesitate to mix it with dry product (wood shavings for example) to balance the humidity. On the other hand, if the product is too dry, it can dry out your tubers. You can therefore spray a nice bit of water on the peat moss.

The wood chip

Wood chips are the least expensive product. Just like peat moss, you need to pay attention to the humidity level if the bag has been punctured. You must also check that there is not too much sawdust (dust) in the container since this limits air circulation and increases the risk of rot. Wood can also absorb excess moisture and allow good air circulation. You can find this product in pet stores that use it as bedding or a COOP, a feed mill, horse breeder, etc. Choose the largest shred.


Sand may be a product to use. On the other hand, it is heavy to handle and can promote rapid germination in spring.

Storage technology

After choosing your product, you can insulate the bottom of the box with a good layer and place your tubers without them touching each other. If the box allows, lay down a new layer of insulation and a new row of tubers. When your container is full, carefully cover your tubers.

Plastic wrap technique

Personally, we don't use this technique since we would have to buy way too much plastic wrap. However, we know of several other dahlia growers who have great success with this technique. This is a good alternative if you don't have a large quantity of tubers.

First, roll the first tuber in the plastic wrap 2 or 3 turns to insulate it well. Place another tuber on top of the first and roll a few more turns. Repeat this sequence with the rest of your tubers. Depending on the size of the tubers, you can make packs of 10 without problem. When your bundle is finished, fold the sides over the bundle to seal in moisture.

The miracle recipe

Unfortunately, there is not one way of doing things that is the same for everyone. Several factors will affect the conservation of tubers: storage location, temperature, humidity, etc. What we recommend is to take a look once a month to make sure the tubers are doing well. You will quickly see if it is too hot or too humid. If a tuber is moldy, throw it away immediately so as not to cause the others in the container to become moldy.

Keep in mind that we do not keep all of our dahlias. Even though we have a well-tempered cold room, we also sometimes lose tubers during storage.

Good luck !

Sarah Beaupré