3,226 Garden Web Discussions | Dahlias

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.

They are first year tubers. I will wait and see. I guess it could be rot but everything around it including other dahlias didn't rot so hopefully it is just going slow.

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.

If you want to get some 4 to 6 inch cow pots, you could pot them up now and plant pot an all when it gets warmer n the ground.

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.

Thanks for the suggestions. I think I'll leave multiple stems (two or three) and see how this bed compares to the single tuber single stem plants in the rest of the beds.

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've seen leaf cuttings mentioned in a book on plant propagation but I've never tried it. I'll have to give it a try. I can see how it could be quite useful if you only have one small tuber of a special variety.

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!

Yes, I have seen beautful dahlias grown in the ground and have done so myself. Just saying that IME they can be successfully grown in pots and done so without much difficulty in my area. Don't want to discourage those having no other choice.

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

Thanks for the idea! I will check it out!

This relates to my situation, but the picture is gone. How big are the plants. How big are the containers?

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

I think that it all has to do with the proper hormones in the apical meristem (crown) of the plant. I actually like to divide my dahlias before any sprouts show. I am just very careful to give each tuber at least a sliver of the crown/apical meristem so that it has the proper tissues and hormones to produce a sprout. That being said, I too am trying to get some stray tubers (that have broken off by accident and without an apical meristem) to sprout. Yes, they do seem to form weird puckered nodules around the tip where they broke off. Maybe the cells are rearranging to produce the proper hormones and tissues to produce a new apical meristem??? I don't know. I just wish they would hurry up ;) We shall see. I am doing the baggie trick with mine right now. My fingers are crossed.

I have a five gallon bucket reserved for all my extra eyeless wonders that I can't quite compost on the theory that all they need are time. Occasionally, I'll root through them, and pull out three or four more that have eyed up on the neck where there was no sign before. Those are all sell/trade/donate tubers... The ones that I'm desperate for something to happen gets the bag treatment, or simply potted up and put in a warm place.

And to answer the question in the headline - they need light when they break the surface - but not if you are going to continue burying them for a while.

Lack of light will make for a long, weak spindly stem.

Gotcha (RE: sunlight). I also got a bit of an answer this morning from one of my tubers. One of my sprouts sticking out of the dirt actually has a couple of tiny little leaves on it! Very exciting. I assumed I was just going to kill all my tubers (not that I'm out of the woods yet).

So my question now: before developing leaves, do the sprouts need sunlight? Is leaf growth triggered by light hitting the sprout? Or is it temp? Level of root development? Something else?

David is probably referring to topping the plant. It is a standard practice to pinch off the top growing shoot after the first three sets of leaves have formed. It encourages lateral branching below, and causes a forking in the top growth. More branches = more flowers.

thanks!

Corn growers use herbicides that kill broad leaf plants(corn is related to grasses). The drift from the spray and even the "fumes" from the spray will drastically affect dahlias that are super sensitive to these herbicides. The "over spray" will probably not kill the dahlias but will cause them to have terrible twisted leaves and stems and not to grow properly and the symptoms can last the entire season.

I have used Round up around my dahlias but have been extremely careful and only do so rarely. Dahlias are not as sensitive to roundup as they are to the broadleaf herbicides used on corn. Still , why use it when a garden hoe does the job?

If weed grasses are the problem, there is a chemical herbicide that just kills grasses and does not affect dahlias at all. I have by mistake sprayed the dahlias and there was no effect on the dahlias. It works reasonably well on the grasses but takes over a week to see the results and may have to be applied a second time. Again, hand weeding and a hoe is probably a better solution.

Hi, Dave. Thanks for the advice. I was intentionally vague because I'm not sure what the farmer uses exactly so I was hoping for comments on all three.
Hi, Ted. That was very helpful. I'm afraid it would be a waste. I might have to make space for them elsewhere.
I planted one in a giant container. So I guess I will start there and see how it does. At least it won't be sprayed.
Thanks, again!