3,226 Garden Web Discussions | Dahlias

Hi there,
the new shoots often are reddish/ purple, especially of cultivars with purple/red flowers, even pink ones. My cultivars with white or yellow flowers send up plain green shoots.
How warm do you keep them? My batch of potted Dahlias didn`t do much, because the wheather was so cold and I keep them in an unheated room. Now after some days of sunshine, they do grow a bit taller.
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You could check the tuber by tipping the container carefully, check the crown and look for squishy parts on the tubers.
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Or just wait, as long as those shoots don`t look like they are shrinking, it should be fine.
Have fun with your first Dahlia summer,
bye, Lin
ps: let`s hear whether you got hooked and how many cultivars you gonna order for next year...

Fertilizer isnt going to hurt them - soilless is recommended because it is generally sterile, so it wont introduce possible fungal virus.
A lot of mixes are peat or coir based, they would be fine to use.
I dont worry about it to much. I use the same mix that I pot my seedling up into, which is a mix of cheap potting mix, pinebark fines, peatmoss & pearlite.
Pro Mix BX and Fafards mixes are the commercial mixes I have seen recommended most often on these forums. If your local places carry them, grab some.

I would avoid mixes that have water retention chemicals added. Dahlias rot if they have too much water. The little bit of fertilizer that they add to potting mix is probably OK. I always say growing dahlias in pots is not for the weak of heart. Lots of problems that are not encountered when they are planted in the ground. A good compromise is a smaller pot(1 -2 gallons) buried mostly in the ground. The soil temps are cooler and there is less need for watering all the time. They do as well or better than dahlias planted in the ground.

David, since that gold dahlia is well established it must have lots and lots of tubers underground, you could probably make 10 plants by separating tubers. Why don't you dig and divide the clump you have to make more? You could also try scraping down gradually to the tubers to see if you could remove one or two from above without digging the whole clump. Another option would be to use some of the sprouts to take cuttings for more plants.

Thanks Steve:
One is enough for me. I try to have as many different dahlias with different bloom times for each color area. Hence I have 4 yellows for the yellow section, 5 pinks in the pink section, etc.
The only time I have duplicates is if I am making a 'hedge' and want the same color or I take a troublesome bunch of tubers and plant several individuals (like you suggested) in different areas to see if they grow either at all or differently. (Like one in soil and one in a pot, etc)

WOW Come to think of it it does work. I have had moles RANCID in my backyard(which is fenced in) and I have been peeing, along w/ my male beagle for about 2 weeks and not have seen moles. AT ALL!! WOW ok 1 problem! Now they are in my front yard. NOT fenced in! What to do?! I guess when I wake up to take my 2am wee wee it will be in my front yard! Thanx for the posotive info I NEEDED IT! I feel like I'm in Vietnam battling these freekin moles! By the way I am a new home owner in Deltona, Fl so this is all new to me! any comments will awesomely help!!!

I had problems with moles digging tunnels through the root system of my dahlias. In the hot summer this would cause my dahlias to wilt so bad in the afternoon because of so much damage to the root system. Many would just die out after a few weeks, even with water every day. My solution was to get that small mesh chicken wire, small enough that moles can't get through the holes in the wire. Then I dug a hole about 12 to 14 inches deep, about 12 inches in diameter. Then cut the chicken wire to put around the wall of the hole, and cut another one in a circle shape to put in the bottom of the hole. Then just filled in the hole with dirt and planted the dahlia. Worked great. No more problems with wilting dahlias in the hot summer sun with reasonable watering.

Thanks,Steve. Actually, I had thought about starting the tubers in a tray and I bought some trays a couple weeks ago. The trays are 24" long and about 6" deep. Maybe I could start them in a few inches of soil and add more as they grow. My only concerns were the possibility of the roots growing together if they were planted to close and also having the necessary amount of light. I do have some shop lights that I used to start tomato plants. Sounds like I will have a new weekend project. Thanks again. unc

Unc,
From the info in your first post it looks like you only have about 3 weeks until you will plant the tubers outside so you shouldn't worry too much about root entanglement or less than ideal light levels. They are not going to grow that much in the next 3 weeks, especially if they are totally dormant tubers. Go ahead and get them started even if they are packed close together as this should get you a few extra weeks of blooming time over the course of the season.

Are they first year tubers?
In my answer (just now) to Califox, I noted that often my 1st year tubers in pots sprout and then seem reluctant to grow anymore. While I do not pack my pots with LOTS of other plants, I will share a larger pot with Glads or pansies for surface/annual color and it could be your other plants are getting the nutrients from the soil and leaving the dahlia short shrifted.
I think they will be fine and waiting is the right approach. But if it did rot, this is why many of us dahlia enthusiasts with LOTS of dahlias have 'graveyards' or ICU areas where we rehab poor growers or extra tubers just in casing we need to plug one in elsewhere.

I am zone 14 in Sacramento and have grown them for years. So our climate is similar. I would dissuade you from growing in pots because it's too hot here and the plants prefer to be in the ground where it is cooler. I do start my tubers in pots in the spring before I transplant to the garden soil. Another advantage of this strategy is that the tender sprouts are protected from slugs & snails when they are most vulnerable. I transplant when they are about 8-12" tall and they are less tasty to slugs & snails.
I have grown some in pots but generally I believe they are only marginal in pots here in this climate.

Last year, as an experiment, I let several shoots grow on a few of my tubers, instead of paring them down to one.
My observation was that the main stalks were weaker, (not the flower stems). It was much more difficult to keep them staked, since there was more to stake and they needed more support. I did get more flowers though.

I have found a few in my tubers this year. One had a root longer than the sprout. It hardly fit in my small pot that I use to root them. If you cut the sprout about 1/16 of an inch above the body of the tuber you will have several primordial inter nodes in that area. Since there are so many, the roots form really quickly and in profusion. If you cut it off above that area and get just one inter node, they root slower. Leaf cuttings are made higher up on the plant and an inter node is cut off the plant and split into two. The leaves are generally shortened by about 50% and the inter node material placed just under the surface of the rooting material. Roots will form from that very small, split inter node. And unlike "tuber" cuttings the leaves of the new plant will appear from the same inter node and the old leaves will die. The very small plant takes about 2 -3 weeks longer to get to planting size. The advantage is that you can take numerous cuttings at one time from a plant about 12 inches tall. My wife took 22 cuttings from a plant about 14 inches tall and got 18 of them to root. That is better than usual and one can count on about 6 or so. This method is really advantageous when you only have a plant as some nurseries only sell rooted cuttings. Last year, I took 6 or so cuttings off a plant of a new variety and only got 3 to root. I did have three plants in the garden and saved the other as a pot root. I am using the tubers this year for the cutting material. And all of this is done with no chemicals; no rooting compounds!

I grew Bee Happy last summer. It is beautiful.Not washed out at all. Just a nice rose pink.Unfortunately it didn't make new tuber.I planted what I dug up in a pot & am anxiously waiting.
I ordered another "Happy" one this year from a different source.The tuber of this is a lot different.More like other dahlias I've seen.The Bee Happy was a little thing,about the size of 2 fingers.
Rose

i just copied and pasted the link into my browser to check it and it worked fine. Alternatively, google this: steve meggos dahlia. That is how I found the article that I read some some time ago, The picture of the large pink one labeled AA 938 is one that he let me try in my garden last year. It was more than amazing, the nicest new giant flower I have grown in many years. It deserves to be named and sold. He told me recently that he may wait another year and introduce it in 2015. My wife fell in love with it too. I will be growing several plants of it this year and our garden will be filled with giant pink dahlia blossoms!

Have you tried a local dahlia organization tuber sale/auction? They're going on every weekend across the country through May.
My club had three Farmer Johns go for $4 apiece today during our first auction... Perhaps you can get one that way.
Here is a link that might be useful: Dahlia Club Sales by state


Wayne, the original post was from 2009, but the question is a good one.
The answer can be all across the board, from some growers swearing that the ground is the only way to grow them for acceptable blooming and size, to others that use gallon pots and grow large dahlias for competition. It seems that climate and the variety you choose to grow, as well as cultivation habits of the grower have an extreme impact on the results. By cultivation habits, I mean the soil composition, fertilizing schedule and watering.
The short dahlias are said to be the best for pots, ranging from 12' to 2'. The larger the pot, the more moisture it will maintain.
Here is a link that might be useful: Growing dahlias in pots


Go ahead and divide them. If you are not planting them into really wet soil then dont worry about letting them "cure".
Hard to believe you grew "dinner plates" in 12" pots! I would think they would need a 5 gallon bucket if they aren't going into the ground. They are usually at least 5' tall.
They had tomato cages and fertilizer and bloomed pretty well. I just didn't have a good place in the ground for them. The bodacious one was amazing... I might have to get another one! Thanks for the reply.
I have we'll draining soil... I remember I watered once and waited to see sprouts before I watered again.