i dont know.. but if i were to try to figure it out...

first i would ID my earliest planting date ...

then i would figure out how long they take to sprout ... and barely get going ... lets say a week or two...

and then i would just lay out some flats of media.. two or 3 weeks prior to going outside.. and get a jump start of a few weeks ... thereby avoiding them getting too large.. needing light.. etc ...

and i would probably just do it in the garage ... and not open the garage door for those 2 weeks or so ... surprisingly.. a closed garage.. especially if it has windows to let in warm sun.. can be one or 2 zones warmer than outdoors .. trapped heat ... and less night cold exposure ...

in other words.. i would stimulate them into early action... but i wouldnt get greedy and try to GROW them early ... if that makes sense ...

i too gave up on them over time.... the fall harvest and winter storing just became to much of a pia ...

ken

It is my understanding that dahlias shouldn't be planted outside any sooner than you would set out a tomato plant. They are sensitive to cool temps when starting to grow, if it is a cold and wet spring the tubers will rot in the ground. A good friend of mine just told me that she lost about 50 dahlias this year that she grows for cut flowers - it rained for weeks and stayed cool after she planted them outside. Her dahlias were started early in her greenhouse. She was really sad that she only had three dahlia plants that made it to flowering this summer.

If you want to get them started early you will need a light set up - cheap fluorescent lights work just as well as more expensive grow lights. They could also be started growing in a sunny window if your area receives enough sunny days during the late winter/early spring.

I wouldn't start them in a coldframe unless you had a heat mat in it to keep it close to 70 degrees day and night. Hope this helps!

Diggerdee, dahlias sure are funny things aren't they! So, I didn't divide the tubers this spring, I had great success storing them over, they looked fantastic, big and plump! I started them in mid April and set out nice sturdy transplants about 8 inches tall in early June. Okay, now the odd thing was that many of these nice big tubers I had expected to flower earlier, while some budded up on normal timing, others sure in the heck hadn't and poked along and flowered a good deal later despite the very hot summer weather! For example 'Akita', last year being a smaller tuber it flowered very early, though had nodding necks, this year being that big undivided tuber it just took its sweet time to finally flower only for the first time about two weeks ago, but with a good number of blooms all on much strong stems this time! 'Go-Go Orange' was new this year, boy that short squat plant just kept beefing up and slow to bloom, now loaded, but even with the weather remaining as pleasant as it has, those new flowers are all pale washed out. 'Rainbow Silence' huge bud covered bush ever sooo slow to open it's flowers, only a few so far, frost will get it before long. My best performers are 'Karma Choc', decent early bloomer and still holding up great, 'Karma Bon Bini' always lovely and I've been quite impressed with 'Ferncliff Tropics'! For next year, I'm gonna start all about a month earlier, say even the third week of March, I have both a 3 seasons solarium and covered veranda that can be utilized.

Prairiemoon, yes, I totally understand, with there being soooo many wonderful perennials, I sometimes wonder if dahlias are just a bit too much work after all, though I'd still wish to maintain just a few of the better performers, but who knows!

i started them one year in my back room, with no direct light in the trays that you can get to start 6-pack's in (i think they hold 8 6-packs, for reference,). literally added 2" of damp peat moss and kinda laid each dahlia tubers (they were all single tubers) half in, half out of the peat moss.

Misted them liberally every day or two so they would not dry out. The eyes finally sprouted and i ended up planting out when the shoots were about 6"

super easy and i had blooms 4-6 weeks earlier than usual

Dee, I am not representative as I have only one dahlia that I overwinted in its original pot in a cold cellar. I took it out and into a sunny warm room on March 9th. It showed signs of life 3 weeks later and on May 4th, still inside, it was so bushy had its first flower bud!

But I get that what I have described isnt practical for someone having multiple tubers.

Thanks everyone. FB it was a strange season. Very cold and wet spring, so the tubers (and everything else in my garden) did literally nothing for months. Then sudden 90-degree days and no rain for weeks. I find dahlias to be later bloomers in good years; this year they are just so late and I'm hoping for a warm fall so I can get some enjoyment out of them.

Linda I did the same thing with the trays and the peat moss, but this was later in the spring and I did it outside. I don't really have a spot inside to try that so hence the cold frame idea. BTW, because of the afore-mentioned cold wet spring, those tubers in trays didn't sprout - sprout eyes, mind you; I'm not talking about full-on growth! - didn't sprout eyes till late June, even early July. Crazy. I had given most of them up for dead and then there were the buds!

Well, thanks for the input. I was hoping someone here would have experience with using a cold frame or small greenhouse to start dahlias. Maybe I'll try it with some and see how it goes. And maybe Jeb is right - maybe I should throw a heat mat in there to keep the temps consistent. I guess I have all winter to think about it lol, and hopefully someone who has done or tried this will add some input by then.

Thanks!

:)

Dee

P.S. Linda maybe you can answer a question I posted in the spring and didn't get an answer to. When starting the tubers in the trays, obviously it's shallow and all the growth is right there. When you plant a tuber directly, you plant it a few inches deep. But when you planted your tray-sprouted tubers, did you bury any of the growth, planting the tuber at the usual level, or did you plant it level with the soil, so all growth was above ground? I wasn't sure which way to go on that this past spring!

i planted at the usual level, trying to leave only 1" of the growth above ground.

Thanks Linda. I couldn't decide how to plant them. Good to know, thank you!

:)

Dee

DiggerDee, yes, if you have a greenhouse do utilize it for getting your dahlias off to an earlier start. Considering that dahlias will sprout shoots in late winter in the cold and dark of a cellar, they certainly do not mind a few cooler nights in the greenhouse as long as it doesn't get too close to freezing. Same with a cold frame or anything such that gets that good bit of extra heat. A cold frame is great cause one can toss a bunch of heavy blankets over it on chilly nights, good ideal to have some plastic ready to also place and secure over the blankets in the event of rain or an unwelcome snow. Here's the thing though, first give your tubers the warmth and stability of your home to get them rooting out and flushing top growth, they'll much more appreciate the warm stable environment over the wide temperature swings of a greenhouse or frame. Also, always go very light with the watering while tubers wake up, this can make the difference between stubborn ones deciding to grow or rot.

I've always wondered about planting out depth of prestarted dahlias and have found if they're set in with a small bit of a basin around them and this slowly becomes filled in over the weeks they've been just fine.

I just saw this photo on Facebook. Someone who has a plot somewhere to grow cutting flowers, had this haul of Dahlias...lol! Wow!

I am finally seeing a few more blooms and they are nice, but half the size I thought they would be, still very nice. It does tempt you to think about doing it again and doing it earlier and better. Brother...this is what gets me into trouble sometimes. lol

"...Brother...this is what gets me into trouble sometimes. lol..."

Yep, lol!!!! That's exactly the way it works!

What a great photo! Reminds me of my farmers market days when I used to load up the back seat with buckets of bouquets. And then drive v-e-r-r-r-y slowly to the market haha!

:)

Dee

FB, meant to add, you're right about that - if the tubers can sprout in the dark of a basement, they should do okay in a greenhouse or a cold frame in the sun, as long as the heat keeps more or less consistent. I mean, this would be in April, maybe end of March, so it's not like it's the dead of winter. I think I will try a little cold frame and maybe get a heat mat for nights and see how things go.

I realize that this year was spectacularly abnormal in terms of cold and rain and the unbelievable delay in growth of seedlings and tubers, but I still would like to try to get blooms even a week or two earlier. So disappointing to wait all summer, get these beautiful blooms and then it gets cold and that's the end! So it's worth a shot, I guess.

:)

Dee

BTW, here is a cool site for dahlias....

Floret Flowers

OMG, PM2, I LOVE her site! I've been a fan of Erin's for years - she wrote for a market gardening magazine years back ( she may still, I just don't get it any more lol) and so I've watched as her farm grew and evolved also - watched in admiration and jealousy lol. She does wonderful things!

:)

Dee

She does and whoever designed her website did a great job!

This is it.... a few of these and a couple more of a lighter colored that is just starting. I was expecting the gold to be that small but abundant, which it's not in full sun. I would say though that the company was overwhelmed with orders and sent mine pretty late.

I forget which one this is, but it's not even half the size I thought it would be.

I also am thinking Dahlias aren't as nice an addition to a bed that is designed for display. If I had a place to grow them for cutting I would be happier too. I haven't even got enough this year to bother cutting them to bring in the house, although if I manage to get a few more, I will try it with the last of the roses.

Dinner Plate Dahlias - do you grow them? If you are going to grow dahlias, I would say these are certainly worth the effort. I have included a nice site if you are interested.

https://www.gardenia.net/guide/most-beautiful-dinner-plate-dahlias