Harvesting Dahlias

Lessons learned from my first year as a Flower Farmer

By JISKA HEALY

This year was a year of many first times. First time new business, first time succession planting, first time no-dig gardening on a large scale and first time Dahlia tuber harvesting. And if I say harvesting Dahlias, I mean harvesting over 2,000 of them.

It took us nearly five full days and a three-girl strong harvesting team to get the job done. Believe me, at 5 degrees wind a strong icy easterly wind and continuous rain it wasn’t pretty, but we got it done in the end.

I need to be honest with you. It was tiring, body wrecking, back breaking work. The girls were great to help me out. Next year we will probably get more help in because gardening and flower farming needs to stay fun right? Why would we otherwise continue doing it.

But I have to say: once the tubers were all out of the ground, labelled and washed and ready for storage I experienced a great sense of accomplishment. We are all go for next year and what we don’t sell in the spring we will put back into the ground for another year’s harvest.

Of course, most of you don’t have 2,000 Dahlias in their front or back garden so harvesting will probably a little bit less cumbersome. I will share with you my top 5 tips for harvesting these fantastic subtropical flowers.

Tip 1: To harvest or not to harvest

I’ve got great news for you: not everyone will have to harvest Dahlias this year. Ireland is known for its soft rainy winters and if you are living in a zone nine fat chance that your Dahlias will overwinter just by themselves.

Do use a generous layer of mulch on top of the dead plants and retrieve them again when all danger of frost has passed. If you are not certain what zone you are living in then click this link to check it up.

Unfortunately for me we live on a mountain 660 ft above sea level and the site is relatively exposed to cold eastern winds. On paper our area lies just between zones eight and nine.

Count in the fact that per 300 ft of height difference there is on average a 1°C temperature difference. With other words: if it starts freezing out there, we are usually the first ones to know.

Tip 2: Be patient my friend...

If you want to dig up your Dahlia bulbs you need to be quite in tune with the weather forecast. A Dahlia will show you when it is getting time to harvest: After the first frost all plants will turn black overnight. And I really mean overnight.

But don’t rush and start digging right from the moment those beautiful lush petals are turning black. Leave those tubers in the ground for a few days, preferably a week or two. The plants will start to reserve all energy in its tubers and you will end up with healthier plants the following year.

Do be careful, however. If the forecast predicts heavy frost after that first night, it is better to dig up the tubers sooner rather than later. We were really blessed with the wintry weather this year. After that first good night of frost the weather cleared up nicely, giving the Dahlias the time to reserve the most energy in their tubers.

Tip 3: Keep your distance

When lifting tubers, you use a garden fork. These pointed tools have a nasty habit of piercing perfectly good tubers (and in my experience always the biggest and best ones) within seconds if you are not careful. When used too hastily you could also end up with snapped off tubers.

This is why you need to dig with quite some distance between you and the plant. I usually guestimate at least ten inches around each plant and even with that distance piercings still happen (I do have very big tubers this year).

Stick your garden fork in a few times around the one plant ad gently lift using your hands to free the tubers from the surrounding soil. If you feel any type of resistance to not use force but try sticking in the garden fork a few more time really loosening the soil.

Tip 4: Wash before you dry

When your tubers are lifted it is time to clean them. Make sure that most soil is off the tubers and stick them in a large bucket swooshing them around. At this stage you can also start checking the tubers for bad spots or rotten bits. Remove them before drying.

After that it is time to lay out all your tubers on an even surface without them touching each other for 2-3 weeks. This pre-drying period will guarantee you a higher chance of them survival into the next year and will help prevent mould from forming.

Tip 5: Only so many goes into the barrel…

…or box, or bags or whatever you will choose to keep your tubers in. Don’t try to cramp as many as you can in the one spot.

I personally use cardboard boxes with aeration holes in it and leave them in there without any type of medium. The humidity levels in my storage shed (a.k.a. our little cottage at the bottom of the driveway) are high enough to prevent the tubers from drying out.

It is also not high enough for mould or rotting processed to begin. If, however you are in a dryer climate or planning to store them in a dryer place I would recommend using moist sawdust or compost to store the tubers in. This allows you to regulate humidity levels better.

That’s it. That is what I do to harvest and store my tubers. I have not talked about the subject of dividing tubers since I prefer to do that towards springtime when the little sprouts are a bit easier to recognise.

I hope this was of use to you. If you have any comments fill in the forms below. I am curious to see what you did this year with your Dahlias.

Next week I will tell you all I know about no-dig gardening and why we use it here on the farm

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