growing Dahlias

It’s November and by now most everyone is involved in some aspect in the final journey in the life of the dahlia, The Great Divide!  The weather has been exceptional for processing our precious tubers, with mild temperatures and a little rain.  If you haven’t started yet cut down your plants and start digging and dividing tubers right away. This year all the club gardens were cut down, dug, and divided on different weekends.  Tubers were divided, dried, and stored quickly to try to eliminate tubers from drying out. All club tubers were put into storage by November 9th.  A Big thanks to all club members on a successful harvest.

            For those of you still harvesting I can offer some suggestions. Some dahlia hobbyists leave the plants in the ground over the winter, with a layer of mulch, and will either let the tubers grow for an early start in spring or divide the tubers and replant.  Where I live, I need to dig each year, or my tubers will freeze.  The second method some guidebooks recommend is digging and storing tubers clumps whole, then divide the clumps in the spring.  This works great if you have storage that has some climate control that prevents the clumps from dehydrating.

            Most dahlia growers in the Pacific Northwest divide their dahlia clumps in the fall.  I’ve been dividing and storing tubers for over 30 years and have changed techniques over the years.  I used to use a sharp knife (stitches) to perform the dividing task but now only use a scissor.  I used to wait a week or two before digging and dividing, but now start dividing once dahlia stalks are cut down.  The tuber “eye” is visible when using this technique.  To start dividing, first locate a tuber with a visible eye.  Take you cutting tool and make a pie-shaped cut on each side of the tuber into the stalk (crown).  Repeat until all the tubers have been removed.  Not all dahlia clumps are simple to divide and may require cutting the clump in half or quarters to expose the eye of the new tuber.  I will frequently leave two or three tubers together to store and divide in the spring when additional eyes will show. 

            Be selective with the tubers you keep.  Make sure the tubers are clean, firm, clear of disease, the neck of the tuber is not broken, and excess stalk is removed around the eye that may rot in storage.  To assure each tuber has the right name, use an indelible pencil or Sharpie to write the name or an inventory number.  Some growers treat tubers with fungicide (solution or sulfur dust) or a solution of bleach (1/4 cup bleach to 3 gallons of water). Treating the cut tuber may reduce the chance of rot or mildew during storage. I used to soak all our tubers in bleach but over time we found there was no real difference with tubers lost in storage. Another option for treating tuber with a natural fungicide cinnamon prior to storage.  I have found that a properly trimmed, clean, completely dry tuber will store best without all the extra preventative steps. 

            Although many of you have already put your tubers to bed, here are some tips for successful storage.  Closely monitor the drying process.  You want completely dry tubers and avoid shriveling and softening.  There are several ways to store tubers.  Tubers can be placed in plastic pots, on screens, newspaper, or paper towels to air dry. A wet tuber may rot in storage and a shriveled tuber may not grow. Drying is the most critical part in assuring tuber survival through winter.

            Many growers use wood shavings, peat moss or vermiculite.  Tubers are placed in plastic bags with equal amounts of storage medium, labeled, then place in tote boxes or Styrofoam boxes.  Another method is to wrap tubers in plastic wrap.  Place completely dry tuber on plastic wrap, wrap tightly, add another, wrap tightly, add another and so forth.  I have never used this method, but many growers prefer it!  Store in an unheated basement, garage or root cellar with a constant temperature in the 40-degree range.

The changing colors, shorter days and rain are moving us into fall as we approach the preparation of harvesting our tubers. Mild temperatures have extended blooming, and have given us the 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 questions I’m frequently 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 soil that drains well 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 it with 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) 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. If you don’t want to bother with the work, buy tubers from KCDS at our annual tuber sale next April!By now you should have walked through your dahlia patch and labeled all the plants you want to save with the correct name, disposed of poor performing/diseased plants, and identified quality plants to donate to our tuber sale for next year. Next, gather your supplies 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, Valley Nursery or online through Amazon. Coarse vermiculite is the preferred size medium. Once you start digging and dividing you will be too busy 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 stalks. 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 pitchforks 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 step-ping on the shovel or pitchfork too 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 stalk, 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 to come 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 winter’s nap!

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It’s April 16, 2023, even though Spring is happening all around us, cold winter temperatures prevail! The next 10 days of weather projections predict a continuing wintery pattern with no sign of warming temperatures conducive to warming soils. Our tubers, however, are waking up in storage and are showing signs it’s time to plant. Spring is busting out all over, but conditions aren’t quite ready to welcome the new beginnings for the life of the dahlia.

The Pacific Northwest has many microclimates that will determine when you can plant your tubers. My yard, even with full sun exposure, tends to be a little cooler than someone who may live closer to sea level. Although temperatures are warming up, nighttime temperatures are still very cool. For most of us west of the Cascades, the first week of May is the perfect time. For those of you living in a cooler area you may have to wait until June. The key to successful planting is the right soil temperature of 55 degrees!

In the meantime, for those of you who need to plant something, start your tubers in pots or trays. In the past I have taken tubers from storage and placed them in trays covered with wet shavings. The tuber eyes start to pop, and roots begin to emerge. You can also start some larger varieties in pots. I then transplant when the PLANT has three sets of leaves. I take lots of cuttings and plant the tubers and cutting plants at the same time. If the soil temperature is right, I will see tuber sprouts emerging and the cutting plants start growing. If the weather is wet and cool, the tubers and cutting plants will just sit there until the soil temperature is right.

Now that you’re ready to plant, here are the basic guidelines to follow:

Spacing: Many new growers ask me how far apart they should plant their tubers. For me I always plant 24 inches apart. For the giant varieties I would maybe space up to 36 inches. For the smaller varieties 18 inches will work. Proper spacing gives you room to groom and cut your blooms.

Drive support stakes into the ground for the taller varieties or use tomato cages for the smaller dahlias. Dig a hole 5-6 inches deep. Before planting the tuber, it is time to add some fertilizer and mix thoroughly in the hole. Over the years I have created a mixture of 2 to 3 TBLS of 10-20-20 fertilizer, 1 TBLS bone meal and 1 TBLS Epsom salts placed in each hole. Everyone has special additives they like as well. These might include alfalfa pellets or meal, kelp meal, compost, and other stuff.

Labeling: Prior to planting you need to create a label for each of the varieties you’re going to plant. Most growers use plastic labels and indelible ink, industrial grade non-fading markers like Sharpie to label tubers. Some use label printers, creating labels that can be used year after year. Labels should also include bloom size, type, and color. As a backup, some growers also create a garden map with dahlias names if labels disappear.

Planting: Place the tuber horizontally with the eye pointing up, two inches from the stake. If a dahlia sprout breaks off, no worries, the tuber will grow another. Cover with 2 inches of soil. Shallow planting like this will allow moisture and the heat from the sun to help the tuber start to grow. As the plants grow taller you can fill in the remaining 3 to 4 inches of soil. Good luck planting but be patient for the right planting conditions!

There is still time to score some tubers at the online tuber sale, club raffle, and other club plant sales that can be found on our website; kitsapdahlias.org.

Spring Ahead everyone! We are only weeks away from the Spring Solstice and hopefully seasonal temperatures will return. My pot tubers are starting to produce new shoots and I will be taking cuttings soon. I also have pepper seeds starting to sprout and will soon start tomato seeds in a few weeks! My little 8 X 10 greenhouse will soon be crowed with all sorts of plants.

March is garden preparation time. Dahlias require 6 to 7 hours of direct sunlight for optimal results but will do fairly well with a minimum 3 to 4 hours. However, blooms and plant health may be affected with lower amounts of light. Plant in an area where plants will have good circulation of air for healthy growth and to prevent mildew. Avoid plants near trees and shrubs that could rob your dahlias of necessary moisture and nutrients. I have one spot in my garden that a tree loves sending roots to my well-watered and fertilized dahlias.

How did your dahlias grow last season? Were the plants healthy with lots of beautiful blooms, or stunted, with unhealthy leaves and few blooms. It’s all about the soil!  In the Pacific Northwest the soil tends to become more acidic after a winter of lots of rain. Dahlias grow best when the soil pH has a neutral reading of 7.0. Soil pH between 6.5 and 7.0 ensures that your dahlias will efficiently absorb the nutrients needed for healthy plants and beautiful blooms.
If your garden was disappointing, you may consider getting your soil tested. You can purchase inexpensive soil test kits from Lowes, Home Depot, Amazon or local garden centers. If you live in Western Washington, for more extensive testing you can try Twiss Analytical Laboratories in Poulsbo (360) 779-5141, website https://www.spectra-lab.com/. The cost of the test is $48. You get test results, but Twiss makes no soil recommendations. Another test site is Northwest Agricultural Consultants www.nwag.com/lab-services. Soil tests start at $ 35.  You can also try this link that has a wealth of information and recommendations: https://puyallup.wsu.edu/soils/soils/. Contact your Master Gardeners for soil testing centers in your locale.

Good draining soil is essential for growing dahlias. I am blessed with good draining sandy loam soil that I amend with organic material each year. The tuber does not like to sit in wet throughout the growing season. Clay-type soils tend to retain moisture longer but can be improved by adding organic materials to break up the clay. Some growers will construct raised beds to avoid this problem and bring in some good garden soil to raise prize winning dahlias!
For those of you who have planted a cover crop last fall, now is the time to chop down and spade or rototill it. Add fertilizer at this time to help feed the soil organisms that break down the nutrient rich organic material. If you did not grow a cover crop now is the time to add organic material such as leaf mold, compost, or manure. Check the soil pH and add lime if needed. You want to make sure that if you add lime now that it is a quick release lime to get full benefit of improving the acidy.  All materials should be incorporated at least one month before planting to give time to decompose.

Many of the dahlia clubs will be hosting their annual tuber sales either live or online this year. If you haven’t had a chance to complete your wish list, you will have a chance to get some of the most popular and newest varieties of dahlias at attractive prices. The Kitsap County Dahlia Society Annual tuber sale will again be online for members and the public. Check out our newsletter or go to www.kitsapdahlias.org for more information. You can also check out the Federation of Northwest Dahlia Growers web page, www.nwdahlia.org/club/ and click on the club links for information on dates of their dahlia tuber sales. Excitement is growing for the “Life of the Dahlia”!!

Hope everyone is enjoying this brief time off from the beginning of a new “life of the dahlia” season. I hope most of you have checked your stored tubers by now. A rotten tuber can take out other tubers stored together, and you could lose an entire variety if not checked.

This month is the time to wake up any of the dahlia tubers you may want to take cutting. Taking cuttings is a com- mon practice to increase the quantity of stock for dahlias that may not make lots of tubers, or with new, especially expensive tubers. Successful cuttings can make a $20 to $30 new introduction more tolerable. If you get 4 to 6 cuttings now the price is $4 to $5! Many growers feel it is better to start the season with growing plants rather than taking a chance of a tuber rotting in cold damp weather.

Tubers or pot tubers are planted in a good potting soil in temperatures around 68⁰ to 70⁰ s with sufficient light. In about 3 weeks after the new shoot has two sets of leaves, a cutting can be taken about 1/8” from the tuber. The first pair of leaves is removed, and the cutting is placed in propagation mix or quality potting soil. Keep soil moist and in about 3 weeks you should notice the cutting with new growth. This is a very abbreviated explanation. Come to the February KCDS club meeting February 21 at 6:30pm and learn how to take your own cuttings.

February is a good time for garden cleanup. Early weeding in the raised beds, retaining walls and fences before weeds and grasses get established will make the weeding easier come spring. Clean up yard debris, old plant stocks, and pruned branches. This will help eliminate some of the places insects and slugs have laid their

eggs. It’s not too early to lay slug bait out to protect the new growth of your perennials. Slugs have always munched on my del- phiniums this time of year. It’s also a good time to repair and sharpen garden tools, sharpen pruners and scissors, and tune up the rototiller! Our 2022 dahlia season is quickly approaching! So get ready and we’ll be planting before you know it!!

Happy New Year to all you dahlia nuts! It’s time again to prepare for the first chapter in the “life of the Dahlia” – the search for dahlia tubers on your wish lists! I’m sure many of you have already purchased your tubers from the commercial growers as soon as you get word their website has opened. Demand for dahlias over the last couple of years has gone crazy with many varieties selling out early.

 The American Dahlia Society (ADS) website can be a resource for tuber purchase ideas. In prior years the ADS mailed out dahlias show reports, trial garden results, Cream of the Crop, Fab 50 for top winners, top new introductions, and popular dahlia varieties. The show reports highlight potential best in show winners that I may want to purchase. The name of the winner is listed, and you can then contact the grower using the Federation of Northwest Dahlia Growers Show Book or classification book. If you like to exhibit these resources can help identify potential future show winners.

Here is a great link, http://dahliaaddict.com , that allows you to search the dahlia alphabetically. Once you click on the dahlia name the dahlia this link lists the growers who carry the tubers! Use our KCDS web site for other links. Other supplier sources can be found using this link, https://coloradodahlias.net/index.php/suppliers/ and in the Puget Sound Dahlia Association annual publication Dahlias of Today and the American Dahlia Association January Bulletin.

This month’s meeting will feature a presentation on the new 2023 dahlia introductions. President Paul Kusche will review each flower and provide a printed list with descriptions and grower contact information. New introductions can be pricey. Taking cutting from a tuber can make the price more tolerable and create two or more plants. Although you can take cuttings from a tuber look for growers who sell pot tubers. These mini plants send up lots of new shoots for lots of cutting. KCDS will discuss taking cuttings in February.

Late January or early February is a great time to perform a quality check your dahlia tubers. This is a must. Look at each bag, box, or container of stored tubers a check for excess moisture and tuber rot. Early detection and removal of rotten tubers will prevent further loss of stock. If you’ve lost a few of your favorite dahlias checking now will give you time to order new tubers.

It’s always good to have a good layout plan for your garden, especially when growing height is important. I have a flowerbed that I can grow dahlia plants that grow over 5 feet in the back row, 3 ½ to 4 feet in the middle row, and 2 to 3 feet in the front row. Most commercial growers will include plant height, but if not available you can research the height or try contacting the grower. A good plan will allow you to determine how many tubers you can plant, while allowing for proper spacing, and determine if you need to order more!! Your plan should include a pathway, entrance(s) and water source. KCDS is starting to plan our display gardens for 2023 now. We want your input on flowers you would like to see planted this year.

I’ve given everyone lots of options to help you complete your wish lists. Don’t delay ordering! Several varieties are selling out!! One of the benefits of your membership to the Kitsap County Dahlia Society is the ability to network with other members to find, trade and/ or purchase tubers on your wish list. Some of our members have inventory lists of available tubers that can be shared upon request. So, you’d better get busy and shop, network and buy, sell, or trade!

The question of digging dahlias comes up often in discussion with new and even current dahlia growers. It is often a good debate and it really depends on the grower what answer you will get. Unfortunately there is not one answer. Let’s look at some interesting bits of information:

1) Dahlias are not frost tolerant annuals.

 2) The roots (or tubers) of a dahlia plant are actually swollen pockets of carbohydrates in the root structure.

3) Carbohydrates convert to sugars for the plant just like potatoes convert to sugar when consumed by humans.

 4) The plant creates the tubers so it has energy for regeneration.

So ask yourself a couple of questions (your answers probably have a lot of “depends on” attached to them): Under what conditions would I leave my potatoes in the ground? What is the best storage method for potatoes?

 Here are options that I hear from other dahlia growers.

 1) I just leave mine in the ground year after year because it is too much work to dig.

 2) I have a cut flower business so I just leave mine in the ground and I get lots of stalks and flowers.

3) I dig mine up every year but sometimes I just store the clump.

 4) I leave mine in the ground and dig them in the spring.

 5) I leave mine in the ground and dig the ones up that I want to replace in the spring.

 6) I don’t have a way to store them so I just leave them in the ground and hope they come back.

 7) I dig mine every 3 years in the fall so the clumps don’t get out of control.

 So, let’s break this down to three simple options:

Option 1) Dig in the Fall if:

Your ground will have a chance of freezing.

You have a storage system and can manage 38-40 degree temperature storage.

Your ground gets so wet in the winter that you will drown and rot your roots.

You want to preserve the quality of your flowers.

You want to have the best show quality flowers.

If you are on new ground and will need to work the soil for the next season.

You have the energy and don’t mind working in the cold outside (Ha Ha Ha Ha).

You are selling tubers and you need to know what your inventory is for the market.

Option 2) Dig in the Spring if:

You want to replace a few and you leave them in most of the time anyway.

You don’t have any other storage method.

Your soil has outstanding drainage.

You have the leaves, grass or compost to cover them with 6” of material.

You want to go to Arizona for the winter and not mess with your tubers.

Option 3) Leave them in the ground if:

 Your ground has good drainage.

You do not have time to dig them this fall.

You have enough leaves, grass, or compost to cover them with 6” of material.

In the end it comes down to this: The two biggest killers of dahlia tuber in the ground are 1) freeze conditions and 2) too much winter moisture. No matter what, please dig, clean, trim and replant your tubers at least every 3 years.

Please don’t plant if your growing bed looks like the above picture otherwise you will be visiting the Kitsap Dahlia Society Tuber Sales every year for replacements. We will appreciate the $$$ though.

We would rather that you have healthy plump tubers to give back to KCDS.

Article and photos compliments of Paul Kusche – Papa Paul’s Dahlia Farm, Olalla, Washington