Breaking tuber dormancy

SteveM · 2025-04-18T01:51:09+00:00

Even with ideal temperature and moisture, the ability of a tuber to break dormancy depends (at least in part) upon the conversion of starch into sugar duri...

Dahlia53

BarryO Thanks, Barry. I have never had to do the baggie step; they always showed signs even in April but I had the little boxes outside so that must have been too cold for them. since I put them inside in open beverage trays, have them inside, a handful are eyeing. Yesterday I put about 2/3 in moistened potting soil and lined the cardboard trays with plastic.l but i ran out of plastic, so have to find more to do the rest. I didn't have any plastic trays recommended to me. Thanks! I'm glad I asked for help with this. Even though light is not a factor, it did seem to help to get them out of the dark and put the tubers inside in bright indirect light. When I didn't wrap them before, they would have broken dormancy far too soon. Since I can't plant til June anyway, my tubers are about 2 wks behind everyone else's to bloom. But other people have better conditions than I do and want their tubers sooner.

I think next year i will be more ruthless and only keep several of each of the best looking tubers and nothing too small (like little finger size). I used to have better drainage on another garden plot, and my tubers were much nicer looking without even any fertilizer.

Teddahlia

"...and develop hair roots within 2 weeks." Hair roots are the main source of water and nutrients for the dahlia plant. You need to carefully preserve them from damage when you transplant the "woke up" tubers. Those hair roots are what give you a head start on the growing season. A tuber with only a sprout and no hair roots has to form hair roots to grow properly. A tuber with just a swollen eye grows hair roots and the sprout at the same time. They are "matched set" . If you plant a tuber with a long sprout and no hair roots, the hair roots need to form before the sprout will grow very much. The sprout will be skinny too. I suppose this is why the late Phil Mingus cut back the sprout to less than an inch or if there was another sprout, removed it entirely. He wanted a very fat sprout to emerge from the soil. Having learned all this from Phil Mingus who grew dahlias for 70 years, I am a bad student as I leave some long sprouts on and have them poke out above the soil. For some reason it makes me feel better when I see that sprout above the soil. All these "best ways" to do something are really just suggestions and you can just plant the tubers "willy nilly" as they say and they generally grow very well no matter how you do it. I always remember the Swan Island method where tubers are tossed into a hole on the platform behind the tractor and they land in the furrow and are covered by the tractor as it goes along planting in 600 foot long rows on the way to planting 450, 000- tubers. 😳

calico20hill

Teddahlia And to think, I got it on my first seedling! Actually, I am reselecting STG with the ones with the darkest backs. I see too many on the market where it is a light red violet and while pretty enough it lacks the drama it started out with. The only thing I accomplished between rain showers today was to plant out 20 started plants or seedlings from parents that showed the very dark back. That is a lot of space to dedicate to one variety out of my 6 raised beds for dahlias!

Dahlia53

calico20hill I know this is changing the subject from my original thread topic and it probably belongs in another topic, but what causes stock to fade or morph or change color? And if we have stock that is sold as one thing and doesn't match what we thought we ought to be getting in the picture, does this mean it has sported or is bad stock and should we start over buying it again? Thanks!

Aha = I read on and I think Ted just answered my question. Find stock as I remember that it should look. All the more reason to take cuttings if one has good stock - and spread it around to the serious dahlia addicts who will keep it going! Some dahlias are notoriously hard to grow. Or genetic decline. Or virus. Or a host of other unknowns. The lesson is, learn to do cuttings of good stock and share with people who take cuttings and dig their clumps. 😁

bloomhjelm

Is there a word or term for that, re-hybridizing? 🙂 to restore a dahlia's gene expressions to its intended ones?

Teddahlia

One of the oldest "tricks of the trade" for growing dahlia is the careful selection of your planting stock to be sure it is healthy and retains the characteristics it is supposed to have. Do we do enough of it here? HH Pink Tigress we grow has much less pink but grows healthy. Missed that selection. When the majority of the stock has "declined" commercial growers cruise the gardens for good examples and take cuttings to "re-vitalize" the stock. Why do they decline? The old funny reply from the 1960s was: "Why is there air?" I never got the meaning of that saying but I think it means in this case, that some stock is prone to a virus(and probably a virus not tested for) or is prone to genetic decline.
The why is less important than the cure of saving only good stock. Or, if all your stock goes bad , get new stock.
We still grow some of this never released 2020 seedling. Why? We like it but not enough to name and sell.

Teddahlia

HH Snowfire was a tricolor variegated but the breeders liked a sported version that was a red and white bicolor with out the pizzazz of the variegation or the extra yellow color. The breeders like the bicolor better but should probably try to get some of the tricolor version back.

bloomhjelm

It's unfortunate that the 800k sellers of dahlia tubers online give you only single photos to judge the soundness of their stock, but I don't know how you would remedy that. Take videos of every variety? Give every variety a grade? We spend so much time giving caveats on the size/firmness of tubers (if we think the buyer is going to be dissatisfied) but almost never tell each other when we suspect the stock has lost petal count, color, vigor, or developed any unsavory characteristics. (Well, hopefully we're not selling stock with blown centers but I wouldn't put it past a new seller.)

Bessie

bloomhjelm I very much appreciate when a seller has multiple photos of a variety. It helps me decide if the purchase is something I'll be satisfied with. When a website is exceptional, with several photos and relevant information, I always reach out to let them know how much I appreciate the information provided.

The American Rose Society publishes a booklet ( 2025 Handbook for Selecting Roses )with an overall grade for each rose variety based on multiple criteria. I used this booklet many years ago when I grew roses specifically to dry in silica gel.

@blown_dry it would a really cool ( also perhaps challenging to implement?) feature for the Dahlia Addict website to allow users and growers to "grade" varieties. What grade is assigned for varieties as a cut flower? What varieties do home growers like for a border, or for cut flowers? or for wedding work? How is the tuber production? How is the vigor? How is the disease resistance? On second thought, this may be it's own website 😃. Also, allow vetted users to upload photos of varieties, and those photos would by agreement be considered open source.

blown_dry

Bessie

Bessie it would a really cool ( also perhaps challenging to implement?) feature for the Dahlia Addict website to allow users and growers to "grade" varieties.

I would like to try to address this with a tagging system, so people could tag a variety as "tall" or "prolific" or "wedding." It's on my wish list!

Teddahlia

Planting time tomorrow at the trial garden at Swan Island Dahlias. The tubers have been started for 30 days in gallon pots of potting soil and that is not technically "waking them up" but rather is "growing" them in a pot and transplanting them into the ground. This is the ideal method to get earlier blooms when growing conditions are not the best. In the month of May several years ago we had heatwave and the soil was so warm the tubers would not grow normally. Many of the entries in the trial garden could not be judged by October 1st, the deadline for submission of trial garden results to the ADS. Some research was done and it was determined that the best method to solve this "hot soil" problem is to have the plants already started with roots so that they can withstand the hot soil. Does it work? We have never had another really hot May but did have a record setting streak in June a few years ago and the plants recovered to be judged that season. And what about areas in the USA where they have warm summers, especially night time temps? I have talked to a show grower in Tennessee who does this successfully. He says the key to having dahlias do well for the shows in September is to have them about 12 inches tall when the hot summer weather starts. This generally cannot be done by planting tubers into the ground as they are only a few inches tall when the hot weather arrives and they do not grow well. The plants that are 12 inches tall remain at 12 inches or so but when the weather cools off they grow rapidly. The tuber plants that were only a few inches tall remain very short and take several more weeks to grow to full size.
And in areas where torrential rains occur in the Spring using this method helps dahlias avoid rotting in the garden during the wet weather. Having said that, in rainy Spring areas, raised beds are much better as they drain much better as the beds are above the ground level and the water can drain out of the bed.

Dahlia53

Teddahlia Ted, this is a wealth of good information, probably a month too late for me but if I do this next year, I'll be consulting this thread! Thank you.

I did put the tubers in pretty damp soil in cardboard beverage trays lined with plastic. Many are eyeing up and some growing feeder roots and I can see eyes and some sprouts ready to break. Some it's apparent by now I can toss; suspect rot by the color of the growing end. Others, I'm waiting to see but at least some are doing something! Thanks everyone for all the input, good conversation, and great ideas and information (and dahlia photos!) That incurved cactus is a beauty in color and form.

the weather here has been so unpredictable, very DRY, and tonight we are due for .4 inches of rain. I wish my dahlias were in the ground! It may be the last good rain they will get til Sept.

ETA, those promised rains didn't come. But it did rain a little overnight.

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