Dahlia tubers often arrive before the garden is quite ready for them.
In many climates, they show up while nights are still cold, the soil is still chilly, or spring is simply taking its time. If that’s the case, your tubers will need a safe place to rest until planting day arrives.
The good news is that storing dahlia tubers before planting is fairly simple. They do not need anything fancy — just the right balance of cool temperatures, protection from freezing, and enough humidity to keep them from drying out completely.
First, Decide: Plant Now or Store for Later?
Before doing anything else, ask yourself one question:
Is it actually safe to plant yet?
Dahlias should only be planted after the danger of frost has passed and the soil has begun to warm. If the ground is still cold or overly wet, it’s better to wait.
The most important thing to remember is this:
Dahlia tubers cannot freeze.
If a tuber freezes, the internal cells rupture, and the tuber will quickly turn soft and mushy. Once that happens, it cannot recover.
If it is still too early to plant outdoors, proper storage matters.
What Dahlia Tubers Need in Storage
Think of storage as helping the tubers remain quietly dormant a little longer.
The goal is to keep them in conditions that are:
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cool
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protected from freezing
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not too wet
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not too dry
A good storage space is usually somewhere around 40–50°F, with moderate humidity and stable temperatures. If you do not have those exact temperatures to not panic, just make sure they aren't in scorching heat or freezing temps.
Basements, cool rooms, insulated mudrooms, and some garages can work well, provided they stay above freezing. A true root-cellar-like environment is ideal, but many home growers do just fine with simpler setups.
What matters most is consistency.
Good Materials for Storing Tubers
If you need to hold tubers for more than a short period, it helps to place them in a breathable storage setup with a material that buffers moisture.
Common storage materials include:
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vermiculite
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wood shavings {only if you are in very humid climate}
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peat moss {only if you are in a very dry climate}
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lightly crumpled paper
These materials help prevent tubers from drying out too quickly while also reducing the risk of trapped moisture.
On our farm, we often store tubers in plastic bins with vermiculite. Earlier on, we used more basic setups and simply kept a close eye on conditions. You do not need a perfect system — just one that stays steady. The vermiculite keeps a pocket of humidity around the tuber in its own little environment. If the vermiculite is bone dry i lightly spritz the top layer of the packed plastic bin with with some water.
Sometimes your tubers will arrive in plastic bags with vermiculite - this should be fine for short-term storage as well, it also creates its own humidity environment inside the bag - just be sure to check regularly, if the bag shows condensation, open the bag for a few hours to dry out and then reseal.
Long-Term Storage
If you need to store your tubers for more than a few weeks, aim for conditions that feel a bit like a root cellar:
Temperature: 40–50°F
Humidity: moderate to slightly humid
Environment: dark or dim, stable, and protected from freezing
Check tubers regularly throughout storage.
If the environment is too damp, tubers may begin to mold or rot. If the environment is too dry, they may shrivel more than you’d like.
A little wrinkling is normal. Tubers do not need to look perfect. You simply do not want them to become fully dried out.
Short-Term Storage
If planting time is only a week or two away, storage can be much more relaxed.
Tubers can rest in a cool indoor space until conditions outside improve. Some growers even keep them slightly warmer — around 55–60°F — to encourage eyes to begin developing.
This can be especially helpful if you want to monitor them more closely before planting.
Even with short-term storage, it’s still wise to check them now and then and make sure they are not becoming overly damp or too dry.
What to Avoid
A few storage mistakes cause most problems:
Freezing Temperatures
This is the biggest one. Never leave tubers somewhere they could freeze, even briefly.
Excess Moisture
Storage that is too wet can lead to mold, soft spots, and rot.
Excess Dryness
Tubers stored in very warm or dry conditions may shrivel excessively and lose viability.
Constant Temperature Swings
Big swings between warm days and cold nights can create condensation and stress the tubers.
What If a Tuber Starts Sprouting?
Occasionally, tubers may begin to wake up while in storage.
This is normal, especially if they are stored somewhere slightly warmer. Small sprouts are not usually a problem. If needed, you can plant the tuber normally when conditions are right. You can still plant a tuber if it is sprouting - plant 4-6" deep, if the sprout is tall enough to go above the surface, make sure you create a mound of soil to cover it and protect if from being sunburned so it can acclimate to being outside.
We’ll cover this more fully in a separate post, but in most cases, a sprouted tuber is simply a sign that spring is on its mind.
A Note About Potting Up
Some growers choose to pot up dahlias indoors before planting time to get an early start.
This can work well, but once a tuber is potted or planted into growing medium, moisture control becomes much more important. Tubers are prone to rot if kept too wet, and any green growth must be protected from frost, and on the opposite end - sunburn.
If you choose to pot up tubers early, be sure they stay warm enough and are not moved outdoors until all danger of frost has passed.
Make sure before putting them in the ground you take the time to harden them off - put them outside slowly over the course of 7-10 days - Day 1 put them outside for an hour, then the next day 2 hours, and so on.
A Gentle Reminder
Once your tubers have been inspected and accepted, proper storage becomes part of the growing process.
With a little care now, those quiet tubers will be ready when the garden is.
And in a few short weeks, what looks like a humble tuber on a shelf will begin turning into the flowers that carry the season.
More Resources available in the Tuber Arrival Guide:
Your Dahlia Tubers Have Arrived — What to Do First
Dahlia Tuber Anatomy: Understanding the Parts of a Dahlia Tuber
Why Dahlia Tubers Don’t Always Look Perfect (And Why That’s Normal)
How to Inspect Dahlia Tubers When They Arrive (What’s Normal & What’s Not)
