Life of the Dahlia chapter 10 – digging and dividing

The changing fall colors and shorter days and rain are moving us into fall as we approach the preparation of harvesting our tubers.  Mild temperatures have extended the blooming season and, for some who planted late this year, have had a chance to enjoy late blooming plants. Our garden looked really messy, after returning from a two- week vacation, with many blooms broken from rain and wind.  We still managed to cut several buckets prior to the start of tuber harvest.

One of the frequently ask questions I’m asked, by many novice growers and the public at the post office, is “do I need to dig my dahlias every year?” I have three different answers to new growers 1. If you have good draining soil and don’t experience cold temperatures, you can leave the tubers in the ground.  Make sure you apply some insulation over the tuber by covering itwith mulch of leaves.  Clumps can remain in the ground for 2 of 3 years; 2.  If your garden area has a colder climate like my garden has then digging, dividing, and storing will be required to save your tubers.  If you exhibit dahlias, you should dig tubers yearly for quality blooms; 3. Or if you don’t want to bother with the work buy tubers from KCDS at our annual tuber sale next April 2024!

By now you should have walked through your dahlia patch andlabeled all the plants you want to save with the correct name, dispose of poor performing, diseased plants, and identify qualityplants to donate to our tuber sale for next year.  Next, gather you supplies you will need including storage medium, buckets, or pots, cutting tools, plastic bags and marking pencils or Sharpies.  Storage mediums such as cedar shavings can be purchased at Farmland or Tractor Supply in Silverdale. Vermiculite can be purchased at Home Depot, Lowe’s and Valley Nursery or online through Amazon.  Coarse vermiculite is the preferred size medium. Once you start digging and dividing you will be toobusy so get prepared.

Next step will be cutting dahlia plants down usually 6” to 8” above the ground.  You can start cutting plants down any time in October. You don’t have to wait for frost to start harvesting tubers.  It’s best to get started before the soil gets too saturated with rain. Once the plants are cut down give the tuber clumps a week before digging.  This wait will give the clumps time for eyes to become more visible as plants try to send up new shoots for the missing stalks. Once I cut down my plants I immediately start dividing because I have lots of plants to harvest.   Remove stakes, drip irrigation or soaker hoses, netting and attach the labels or tags to the cut stocks.  You don’t want to mix up the dahlia varieties you worked so hard to grow.

Now it’s time to dig!  Sharp shovels and pitch forks work very well for digging each clump.  I use a 22” wide pitchfork that gives plenty of support when prying out the clump from the ground.  Give the plant a littles space, maybe 10” to 12” from the stalk, to start digging.  A common mistake for first time diggers is stepping on the shovel or pitchfork to close to the clump.  I have cut off or pushed my pitchfork through many a good tuber.   Dig a circle around the stalk, then lift the clump gently from the ground. Transfer labels to the dahlia stalks early so you don’t end up with no-name tubers.  

Once the clumps are dug it’s time to remove soil, first by gently tapping around the stock, then by gently spraying with water using a nozzle.  You want to avoid high water pressure or brushing soil from the tuber.  The skin is quite soft and can easily be damaged. Trim the small roots from the ends of the tuber.  Tubers should be divided no later than 2 or 3 days later to avoid shriveling.  If you can’t get to all the clumps, leave dirt around the clump until you can process that clump.  It’s best tocome up with a game plan of how many you will dig, wash, and start the dividing process. Once divided, labeled, and dried, transfer into storage media for a long winters nap! The newsletter will have the KCDS schedule for cutting down, digging, and dividing our tubers.