That is outside my experience, though I have extended blooms for a month by bringing pots in a sunroom... The blooms were below average.

You might want to try contacting Nikki at Tall Grass. She grows in a hoop house, as well as outside, and does quite a bit of cut flower sales.

Just please understand that this is digging time, and getting any timely response right now from anyone that counts on dahlias for their living would be amazing.

Good luck, and please report back here with any findings! We'd love to hear!

Here is a link that might be useful: Tall Grass Farms

thanks cc I went to tall grass web site it is great. I will let you know what I discover. Lynn

Hi Lynn,

This is Nicki from Tall Grass Farms and I am happy to share any info on growing dahlias in a hoop house. We have had several years where we kept getting frost in the last week in August, and decided we had enough! We put up our first hoop house and now we don't know how we survived without it. We plant around the first of April, start cutting around the middle of June and cut until the end of October. You can extend the season even longer but generally need to add some sort of lighting as the stems become very weak. In the hoop house the flowers are much quicker to re-bloom after cutting, and with much longer stems.

We have pictures of our greenhouse posted on our facebook page at Tall Grass Farms if you want to see what it looks like. We will have a few updated pictures in the next few days showing the end of the year tuber harvesting. We have about 800 plants in a 20x96 hoop house however, this makes it too crowded. We will go back to our old layout with about 600 plants next year.

Thanks CC for the mention on garden web and congrats beigestonehill for landing what sounds like an awesome job :)

Hey Nikki, thanks so much for the great information about dahlias in a hoop house. We have not had a frost here in Virginia yet but my dahlias are but done blooming. I assumed it was the change in light. Being that the owner of the farm is gone from mid June until Sept there is no need to get blooms early. I may put a small hoop house up to grow the dinner plate dahlias that my boss loves because they get beaten up in bad weather. I plan on sending the information about your web site to the owner of the farm because she does all the ordering in the spring. Yes I feel so lucky to have such a great job, just planted 4000 tulips; spring will be fantastic. Thanks again for getting in touch and CC for bringing to my attention to Tall Grass Farm.

Nicki, just for comparison's sake, when do you plant the outside dahlias, and when is their window for bloom production?

We usually plant outside around the middle of May our first blooms are usually in mid July on a good year with our first frost usually the last week of August

Have you ever tried, before your hoop house, to put up a plastic row cover to extend the season on both ends? Would you need double plastic with an air buffer between to simulate a larger hoop house, do you think?

CCvacation: We have not done row covers before. Next year though we are going to try something called 'caterpillar tunnels'. They are essentially low cost high tunnels. You can find an article about them in the link below.

Here is a link that might be useful: Caterpillar Tunnel

Thank you for that article! Very interesting.

We put up that kind of structure with bird netting for our blueberry rows, and I had wondered about adapting it to my dahlia rows. Problem is that I will have six-foot t-posts for my support system every 18 feet in the fifty foot beds.

I'll have to think on this for this spring.

Just signed up for the other site CC thanks looks like a great spot. I will spend a lot time there this winter

Good deal!

And I'm looking at that 'Growing for Market' site, thinking that would be mighty useful reading for anyone hoping to sell cut flowers but not sure how...

Here's an excerpt from a 'member-only' article...
"Dahlias are spectacular cut flowers that always command attention at the farmers markets. The main season for field-grown dahlias is late summer through fall, but if you have a high tunnel, you can get an early start by taking your own cuttings in January. Dahlia plants from cuttings, planted out in April in an unheated high tunnel, will produce harvestable stems by late May here in Michigan."

CC, I wrote that article for Growing for Market!

We extend the growing period for Dahlias in unheated high tunnels. Extra lighting is essential at the beginning of the season. There are some growers who leave the tubers in the ground during the winter months in their high tunnel by mulching heavily. This is done in the center bed only as it is too cold near the outside walls.

Dinner plate size Dahlias are best grown under cover for height and bloom size. Dahlias are heavy feeders, and it's important to remember to fertilize them more often when grown under cover. We use a compost tea nutrient mix.

Regarding placement of tuber orders, now is the time to place your order with Tall Grass Farms. I highly recommend them as a supplier. We have ordered some beauties for cut flower production. As growers, we try to place orders when tubers are being harvested. Because we are eternal optimists, we are always thinking ahead to the next growing season.

The Insider's Guide to Cut Flower Dahlias by Lane Greer is a nice book to have on hand.

Greetings, Flower Farmer! May I ask what part of Michigan? I have lots of family up there.

How do you provide light in the tunnel during spring? Shop lights on shelves is the typical inside setup, but I am having a hard time imagining enough light from shop lights strung along the top...

Snarq and FF both, how do you irrigate inside the tunnels? Leaky hose, T-tape, above-sprinklers? Do you deliver fertilizer via the water source, or apply that separately?

Hope tubers are tucked safely away!

We currently have overhead misters however next year we are also going to run drip line down the center of the rows.

The misters are great for while the plants are small but once they start to get flowers the overhead misters make the plants to heavy and can cause branches to snap off.

Once they are at the point that the misters make them to heavy we will shift to the drip irrigation.

How did you come to use misters as an irrigation tool? That is a common thing for large greenhouses to do with plugs and annual seeds... Keeps the humidity up and avoids disturbing the soil and roots. Was that how your hoop house was used before dahlias were grown in there through the season?

Do you run fertilizer through the misters? This is something I've been considering doing next season, but haven't figured out the mechanics of it yet.

No, we put the misters in specifically for the dahlias. We run the misters while the plants are still small and shift to the drip irrigation when they get bigger.

Something we might try next year, once I figure out exactly how to do it, is instead of drip line have some kind of upside down mister. The thought behind that is the spray from the mist on the underside of the leaves helps keep the insect population down.

We only fertilize once, with a slow release fertilizer, and that is when the tubers are planted.

Insect population, in the hoop house? Didn't actually consider that! Would have thought populations would be reduced...

What insects do you battle? I'm assuming aphids and white flies... Is it just the smaller pests that can sneak in, without natural predictors to reduce population?

Please excuse my naïveté. Appreciate your input!

A perfect environment for dahlias is an even better environment for insects :)

Thrips are our main enemy. They come out of the wheat fields that surround us. The misters are also good for helping clear out aphids.

Haven't had to battle thrips yet (knock on wood).

I've heard about really hard insect battles from dahlia growers living next to monoculture farming... Thankful those fields are not too close to my blooms.