Storing Dahlias over the Winter

To accompany our Instagram Stories on ‘Overwintering Dahlia Tubers’  here are my top key points

Rule #1 is keep your Dahlias dry while they hibernate

We don’t wash our Dahlia tubers until the Spring as we find this just discourages the likelihood that they will not freeze or rot.

Rule #2 gentle humidity and ventilation

Over the years we have tried many methods and have found that leaving them with a layer of soil covering them increases success significantly!

This stops them shriveling and getting wizened.

You can use vermiculite instead which works well but it would just be too expensive for us here at Swan Cottage.

Rule #3 steady temperature

Store in a garage, shed or outhouse.

It’s important that you don’t use a shed with a felt roof, these buildings can soar in temperature on sunny days even in January, this will quickly kill off your precious tubers.

You need a nice steady temperature, not too hot or the Dahlia’s will try and wake up and not freezing or the tubers will burst due to the high water content in them. Just the same as you can’t freeze raw Potatoes or Tomatoes, they turn to mush on defrosting…

Pick up a Min/Max Thermometer and monitor your proposed storage place.


Pot Grown

If you have been growing your Dahlia’s in a pot, then you can just put the pot, soil and all into a garage, shed or outhouse.

We let the pot dry out completely, then add a scattering of organic slug pellets for super safety.

(Organic slug pellets contain Ferric Phosphate as an active ingredient. … If the pellets (or the slugs which have eaten them) are eaten by birds, mammals etc, they will suffer no adverse effects).

Garden Grown 

In warmer places with very free draining soil you may often ‘get away’ with leaving them in the ground, however you might not be getting away with it as much as you think and 3/4 of the Dahlia could be dying off each year leaving just enough to re-shoot…

Covering your plant in situ with a cold frame will dramatically increase the chances of survival, as long as this keeps the soil ‘dry’ it might not work on a slope or in clay soil…

Field Frames 

Our Dahlia’s planted out in the field under Neil’s frames can be left just where they are.

We have very free draining soil and a fairly flat site.

Once the frost cuts the plants down we turn these growing frames into cold frames by sliding reusable lids low over the plants. We can wrap the whole frame in packing wrap for the ultimate winter protection.

Storing Dahlias over Winter / overwintering Dahlia Tubers

We had 100% success with this method even during -10C degree freeze of 2017/18


Dahlia’s that are planted around the garden and don’t have the protection of the frames are lifted!

Storing Dahlias over Winter / overwintering Dahlia Tubers

We lift with around the middle to end of November, lifting with all the soil that does not fall away, Tubers are packed in crates which have fully vented sides and lid so any moisture can easily escape.

Storing Dahlias over Winter / overwintering Dahlia Tubers

We then stack them our tin roofed outhouse (see Rule #3)

During cold spells we pull old blankets over the stack…

Whatever method you use remember to label!


Zoe x

We’ll be here to cover the whole flower growing year. Thank you for following your support really does means so much x

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Zoe Woodward Swan Cottage Flowers © Ferri Photography


6 Comments Add yours

  1. Mimi says:

    Where do you get the crates? I’ve seen a lot of people using wholesale bulb crates but I don’t buy enough bulbs to get those

    1. Swan Cottage Flowers says:

      The crates come from wholesale suppliers. We tend to just use pots if not planting in the ground and only use crates for storage.

  2. Jo ASTILL says:

    I have a dahlia plant in a pot which was badly hit by frost. Is it a lost cause or will it grow next year? Thanks

    1. Swan Cottage Flowers says:

      No the frosting of the leaves actually helps to put the tuber to sleep, just ‘left the tuber’ or store the whole pot dry in a frost free place until Spring. We’ve recorded some free videos on the whole ‘overwintering’ process on Instagram

  3. Sitemap says:

    Just wanna admit that this is very useful, Thanks for
    taking your time to write this.

    1. Swan Cottage Flowers says:

      Thank you so much for being so kind

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