Dahlia tubers (how to store them).

Lifting dahlia tubers is surprisingly a quick and easy job, especially if you do it every year. If you are growing your dahlias in a sheltered spot then you don't necessarily have to lift them. But if there is a risk of the ground getting too wet where the tubers can rot, or if you have harsh frosts which could penetrate the eye of the tubers (the stalk where the growth comes from) then it is better to lift them. I have three sets to show you here.

The first set of tubers were lifted after only one year of growing. Only three tubers have formed so lifting this set was simple and quick.

The second is a dahlia tuber that was left in the ground last winter. Again, simple to get out and it comes as one whole clump which can be easily divided down the middle with a sharp spade to give me two plants next year.

The third dahlia is one that I have left in for four years, that's right, four years! It was back breaking to get out!

Dahlias, when left in the ground, store energy into their tubers for the following year's display in the same way that bulbs such as tulips or gladioli do. However as the tubers swell in size over the years they produce more tubers, baby tubers if you will. And if left to their own devices they multiply and multiply, killing off the old tubers and repeating the cycle with new tubers. But if you divide the clumps you can spread your favourite variety into into other areas of the garden for free!

There are however some things you need to look out for.

1, Never use a hand fork to dig up the tubers, I did this before my morning coffee in a sleepy haze and sure enough went straight through a tuber which now has to be discarded.

2, Check the tubers over for any mould or rotting. To do this, gently squish the tuber with your fingers. If they are firm then they are perfectly healthy and will re-grow next year. If any are soft or mushy then twist them off and discard them.

3, If by accident a dahlia tuber snaps away from the cluster and it does not have an eye, unfortunately this will not grow and it will need to be discarded. Each tuber needs to have an eye. In the image below you can see the old eye. But you can also see the purple sprouting of new eyes.

So let's go over step by step how to lift and store your tubers.

  • Start by gently moving the soil away from the tubers

  • Gently lift the tubers out as a crown as best you can.

  • With your fingers, brush away as much soil as you can from the tubers.

  • You can either wash the tubers in a bucket of water to clean them off or leave them 7-10 days for the soil to naturally dry and then brush them off.

  • Make sure to label them.

  • You can either store them in an old plastic fruit basket that you can ask most supermarkets for. Or you can use any wooden box with some sawdust in to help keep them dry.

  • Next think about where to store them, ours go in the shed because it is also insulated so the frost won't come in. A cellar or garage will also work, as long as they will not get damp or cold. If you know your garage gets cold and frost may get to the tubers, buy some horticultural fleece to lay as a blanket over them.

  • Always check your dahlias throughout the winter, once a week is perfect. Lift them up and turn them over checking for damp, mould and moisture.

The 'eye' of a Dahlia is where the stalk joins to the tuber.

Handle the tubers gently so that they don’t snap off but make sure they feel firm.

A cluster of new tubers has formed, but this whole crown could be divided.

This is where to make a clean cut with a sharp spade to divide the plants so that there are eyes to grow from on both parts. You only need a spade if you can not use shears or a knife (with bigger clumps).

Dividing dahlia tubers - the golden rules.

Dividing tubers doesn't have to be a nail biting experience but there are some rules we need to follow.

  1. A tuber will not grow if it does not have an eye.

  2. Any new clumps that you divide need to have at least three tubers attached to it.

  3. If in doubt wait till spring, in spring new eyes will be easier to recognise and you can discard the "mother" tuber which will have shrunk back with no energy left in it.

  4. Any tubers with mould on them or which aren't firm will be no good.

  5. Disinfect your knife or secateurs between each dahlia set.

  6. Store them where they will not rot.

  7. Most importantly for your first year of dividing, only divide one that ISN'T your favourite. See how it fares. Dahlias don't have to be divided every year, so if in doubt leave your absolute favourites for a year until you are confident about the process

But that's it! Don't let it stress you out! If you have any questions, feel free to ask. Come spring we can plant the tubers in pots indoors and even take cuttings from the new growth!

As always friends

Happy Gardening


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