3,226 Garden Web Discussions | Dahlias
The classic area to store dahlia tubers is in the unheated garage but next to the wall of the heated house. Even in rather severe climates the tubers stay above freezing if enough insulation is used. Old blankets, painting tarps are some items that can cover them. Picnic coolers in that location work well too. A remote thermometer can be placed in the storage area and it will help you monitor temperatures. If it is approaching 32, one can move the tubers inside the house for the duration of the cold snap. Tubers will not sprout inside the house unless they are warm for several weeks and will return to dormancy easily when returned to the cooler area.
I've mostly stored my tubers in my unheated unfinished basement which stays around 55 through the winter. That works pretty good but is warmer than ideal. I got tired of hauling them downstairs so I left some in my unheated garage against the north wall of the house and that worked even better so I'll probably just do that in the future with the tubers I don't leave in the ground. Another idea would be to use a vegetable clamp like farmers use for potatoes and other root crops. To make a clamp you just make a big mound with all your potatoes (or dahlias) and then cover it with soil or other insulating material (leaves, woodchips, mulch, etc.) to whatever depth you need to prevent freezing. I would also cover it with clear plastic to keep dahlias extra dry.
***Steve
How did you over winter them in the ground without then being killed by snow and frost? Did you have a temporary greenhouse structure built over top of that garden or something? Christ, I planted my tubers over 6 weeks ago and the tallest plant is maybe 6 inches, and I just was finally able to snip the stems at the 3rd leaf level on just 3 of them so far, and that was just a week ago! Granted, it's been cool here for the most part, except for a heat spell a that ended about a week ago where it was in the high 80's to 90 degrees and humid for about 5 days, but just 1 day before that heat spell began here in northern De, it was high temps in the 60's.
Usually if I plant unsprouted tubers around May 25 they are up in around 12-14 days, and ready to be topped at their 3rd leaf level within 2 weeks of that time or so. But then again, the daily high temps are usually steady in the high 70's to 90's by late May into June, and the spring rains are usually over by then.
But it's been in the Mid 70's all week, and we've now had about 26 straight hours of moderate to heavy rain due to the current storm. I'd bet we've gotten another 2-3 inches of rain in the last 26 hours! I fully expect more of my already weakened dahlias to rot.
Next year I think I'm gonna pay a local greenhouse to let me place a few pots in their heated greenhouse in early April, and I'll start some of my tubers there. Maybe even early march.
Woohoo, I finally got some good rain! At least 1.5 inches of nice slow steady rain thanks to Andrea. We were on the edge and got just the right amount of rain with no wind. :) My dahlias are lovin' it! They are going to grow like crazy this coming week with the fully saturated soil and nice moderate temps in the mid 70s.
HighlanderNorth, here's what I did to overwinter one 4x16 foot bed of dahlias last winter. The bed is a raised bed constructed two concrete blocks high, 16 inches. (See the picture.) So the dahlia tubers are all above grade and will not sit in saturated ground over winter no matter how much it rains or snows. I mulched the bed in late November with about 8-10 inches of dry leaves. Lastly I covered the whole bed with a 4x16 foot sheet of clear 4mil sheet plastic and weighted it down with bricks all around the edges so it wouldn't blow away on a windy day. The plastic sheds water which keeps the soil from becoming saturated and keeps the leaves dry which maintains their insulating value. I used clear plastic because that allow some sun to penetrate and helps warm the leaves and soil on sunny winter days. Along about early April I simply removed the plastic and part of the leaves and let the dahlias do their thing. All of the dahlias survived and most of the plants are huge already but a few looked weak and one i replaced. I don't know what was different about those that weren't strong right out of the gate.
It worked so well that I'm going to do the same thing with the other 3 raised beds that I planted with dahlias this spring. I will leave the clumps I overwintered this past winter for a 2nd winter. I'm curious to see how much bigger the clumps get in their 3rd season (2014.) I'm hoping they don't get much bigger but instead stabalize at what would be their natural maximum size as a tropical perennial.
I think one could accomplish the same thing, keeping the tuber clump above grade, with mounded raised beds. The thing I don't like about mounded raised beds is that they tend to become rounded instead of flat on top and shed much needed water during summer thunderstorms. You could also use a simpler construction method and build simple raised bed walls using treated 2x12s filled with good well draining soil. HighlanderNorth, you should give this a try next winter i think it would work well for you too.
Yes, I definitely top them at the 3rd leaf level. I have noticed their stems thicken considerably within 2 weeks of being topped too. But that's usually with tubers that grew fairly thick stems to begin with. Many of last years tubers that I over wintered are growing thin, spindly stems. I hope topping them, and time will rectify the problem(if they even survive this latest deluge of rain!)
I would have, but we are actually removing what I think was insulating them. There is a wood platform that extra siding for the house was stored and and they were popping out from under there. But we are removing the platform soon because it's an eye sore. I dug up about 10 bulbs and I went back out there this morning and found more plants popping up. There are probably another 10-20 more bulbs under there! Crazy! My father in law is the one who told me that it's not possible to keep them alive in the ground here, but we did have a pretty hard snow pack this year.
Hmmmm - over wintering in the ground in zone 4 is really unexpected. I sure wouldnt count on it happening again.
There is certainly time for them to bloom for you this year. From what I have heard, those exceedingly long daylight hours make up for such a short growing season in Alaska.
I don't think that starting dahlias in zone 4 in April is late. Actually dahlias are native to Mexico, so they aren't cold weather plants and this season has been even cooler than average in the northeast if not everywhere, and dahlias don't grow very fast when it's cool outside. Plus in zone 4 you probably wouldn't want to plant them outside til late may anyway. I started mine in late April in Delaware, zone 7, and it was so cool here that they have still only grown to 5" tall so far! That and the crazy amount if rain has caused some tubers to rot and die. I tried growing mine in pots then transplanting them in the ground once they were over a foot tall and found that they don't seem to like being transplanted after establishing their roots in a pot, and the ones left in pots faired even worse. I Start my tubers either in the ground in mid to late May or let them sprout in pots them put them in the ground.
As far as whether your tubers will come back, I've had a few sprouting stems rot due to excessive rain this spring, but then I pulled the tubers from the ground and dried them off and replanted in drier soil and a few grew new stems.
Those who are exceedingly curious about the status of their tubers can use their trowel and carefully lift the soil around the planted tuber. As soon as you see any growth, stop lifting and pat down the soil. The process will not damage the sprouting tuber if you are careful. Of course, I assume that you placed the plant tag exactly on top of the planted tuber so that you know where the tuber sprout will occur. You will find that most will have sprouted but have not yet reached soil level. You may find a totally rotted tuber too and their is no hope for that one.
Hi lizalily,
Thanks for confirming my guess, bugger, but at least chucking is easier now with the tubers still sitting in a container. And with all this horrible cold wet weather I haven't seen a single aphid/ blackfly yet, so probably no spreading of those viruses.
Well, better luck next time, bye Lin
It always hurts to throw away a dahlia you were ready to love. If there is just a subtle sign of virus I would feed it up and try to get it to be healthy enough to over come it, but since I often sell my extra tubers I want to make sure I am not passing on virused stock. I would try to obtain that one from a different supplier if they can not provide you with a healthier one where you bought it.
I have no direct experience with this but would think if you're soil is dense/heavy, you'd run the risk of rotting out your tuber if you plant them deep. Have you pinched them back after 4 leaf sets tall? This may help them get more stout but you have to get them to the light! If no one else gives you a definitive answer, experiment, plant some deep, some others not. When i plant tomatoes and sunflower starts deep i do not remove the leaves. Good luck!
I just leave them in the ground. Both the orange and the purple dahlias are from last year. When the foliage came up for Brian's Sun, I put a tomato cage over it because I thought it was Purple Splash, which was super tall last year. I was wrong, and now Purple Splash is coming up behind Brian's Sun without a cage. Hmph. I might try to lift the one, but not if it's going to break anything. I'm super impressed with Brian's Sun, very full and bushy.
The small, red dahlia in the picture above is potted and from two years ago. I have to be really careful not to water it too much so that the tuber doesn't rot. We get 50+ inches of rain a year here, so that's a real worry. :/
Brittie, looks like you have success with Dahlias. I am in New Orleans area, almost identical climate to you in Houston. I have heard dahlias don't work here in the heat and humidity. Do you find that to be a fallacy? I bought some called Sky Angel from Lowe's to try in pots because I was afraid to put in the ground as I'd heard they don't like it here. Any tricks/tips for us in the hot humid South?
I didn't mean to imply that I got a lot of flowers out of a single Kelvin Floodlight, maybe 15, I was only saying that it started blooming early because I gave it an early start in a pot and then transplanted it into the ground and it continued blooming until late in the season. Like David mentions, the dinner plate varieties don't produce a huge quantity of blooms. I think my top producer was Maarn (class M) which I orginally bought from Swan Island. I lost count of how many flowers I cut from it but it was quite a lot, maybe 30+ from the best plant. Note that it had many more buds and blossoms than that but for cut flowers you can't always use every flower due to misshapen flowers or stems that are too short. Sometimes I also strip buds off to make smoother stems.
I got a fairly long bloom season the year before last with Vassio Meggos bought from Swan Island. It's listed as producing 9" flowers, but I allowed it to grow 3 main lateral stems after topping at 3rd leaf level, and I didn't do any disbudding, so it didn't grow any 9" flowers, but they were usually averaged from 6 - 7.5". Oddly, once late October rolled around, Vassio Meggos actually started its most prolific bloom phase to date, with 8 flowers on it at once! Unfortunately we got our 1st hard frost on like Nov 2nd, which wiped most of them out before they had fully opened. I'd say I got a total of 20-25 flowers on it in the 2 months it bloomed. But on my one Freckle Face plant from Swan Island 2 years ago I got 80-100 flowers of 3 - 3.5" in nearly 3 months of blooming, and its listed as a 3" flower producer, so even with 6 laterals, almost no disbudding, it still always grew flowers of at least 3 , at least til the end of October when the suddenly got small due to the colder weather and serious lack of sunlight.