The obvious problem with this technique is that you cannot see the sprout under the soil and therefore you do not know when to cut it off. And many sprouts do not make roots because the bottom of the tuber makes roots. Having said these comments, the cutting will fill the new pot with root in record time.

>> The obvious problem with this technique is that you
>> cannot see the sprout under the soil and therefore you
>> do not know when to cut it off.

That is true but by using a light weight soil-less mix (or maybe just vermiculite) for the top 3/4 inch that covers the eye it is easy to brush away to check for roots. The bottom of the pot can contain regular potting soil to feed the tuber through the fibrous root system that emerges from the bottom of the tuber. It may also be possible to determine when to check for roots by the number of days after the sprout emerges or maybe by the size of the sprout. i will experiment further with this idea and report my findings.

I just took several cuttings from tubers buried under the potting mix. None of them had roots. I have seen them but they are rare.

I have been taking more cuttings lately but i too have found that not many of them send out roots while they have an easy source of nutrients from the tuber. The few that I have been able to separate with roots really take off quick though. Two pots I checked today had roots coming off the sprout but I looked very close and couldn't see any signs of secondary eyes so I left the tuber connected and I will leave those to grow on in pots for later transplant.

Here's a picture of a dahlia sprout with a nice root that could be separated from the tuber along with the sprout, but I couldn't see any secondary eyes so I just repotted it.

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(The tuber has fibrous roots out too.)

I would have taken the cutting about 1/16 of an inch above where it attaches to the tuber. It will send up more shoots from that area, I have taken many, many thousands of cuttings and this is a pretty typical situation.

I couldn't see any signs of other eyes. Do you think they are just very dormant? On other tubers that have large sprouts like this I can easily see multiple secondary eyes that are waiting to replace the primary sprout but I couldn't see anything like that on this one. Do you think more eyes will appear if I cut this primary sprout? Maybe I'll take this one back out of it's pot and cut the sprout off just to see if this wakes up eyes that I can't see.

I have a cutting question for you guys. I'm going to try taking cuttings of my dahlia sprouts for the first time, but am a little scared. My other garden cuttings have not gone well, most started rotting, some just died. I am scared to try it with the dahlias because they are so precious to me. What rooting mediums do you guys use and what techniques work for you? The first couple of batches were done in soilless mixes or soilless with perlite. My last batch with just perlite and this one seems to have less rot but some have just died. Thanks!

I apply a light coating of rooting hormone powder then plant the cutting in the damp 100% vermiculite. I place the potted cuttings inside a white plastic bag for humidity (spritzed occasionally with a spray bottle.) I try to hold the temperature held around 75F degrees. They get around 12.5 hours of daylight and then another 2 or 3 hours of artificial light in order to give them 14 hours of light. After 8-10 days I start pulling on them to check for roots. As soon as they have about 3/4 inch roots out like in the photo below I pot them along into 1 gallon pots of potting soil and they stay there until time to transplant into the garden.

{{gwi:636052}}

I started my first round of 15 cuttings on March 19. The first cutting rooted in 8 days and there are still 4 remaining from that batch that have not yet rooted (after 20 days) but have not rotted either. Interestingly 3 of these 4 are the same variety so perhaps it's just slower to root than other varieties.

"Do you think more eyes will appear if I cut this primary sprout?"

Typically two to three new eyes will appear after cutting the primary solitary sprout. Depending on the variety, sometimes the first cutting has a larger diameter then successive sprouts/cuttings, and takes much longer to root.
I've heard it estimated that tubers can exhaust themselves after three to ten cuttings taken, depending on variety.

If you used a magnifying lense to look a a dahlia "eye" you would see one larger "eye" in the middle and two more very small "eyes" on either side. When the central sprout is cut the other "eyes" sprout. And each of those smaller "eyes" are also actually three "eyes" and they can sprout too. Each successive sprout is smaller in diameter and eventually the tuber "runs out of gas" and the last sprouts are very skinny and fragile. Smaller sprouts root just fine but take a bit longer to grow into full sized plants. Some tubers only send up a few viable sprouts and others can send up 10 or more. If you are taking cuttings from a small clumps called a pot tuber, it is possible to get 30 or more cuttings as the clumps has several "eye sets".

Grace, the type of soilless mix doesn't seem to make much difference. There are growers that are all across the board with straight or different proportions of peat, perlite, vermiculite, sand, and oasis foam, and all work great.

Also, there are a great number of experience growers on both sides of the fence with rooting hormone, with more and more saying that it does not help one bit. (Teddahlia would be one of them) I've never used it with my cuttings, and have great results.

The temperature is the other point of contention. More and more growers are saying that 70 degrees is perfect for rooting cuttings, and more or less actually inhibits the process.

Finally, the one thing all growers seem to agree with is humidity. It is essential to lock in moisture for at least ten days to avoid the cutting from wilting, and after rooting, should be weaned off the humidity gradually.

It's possible that you have damp off disease, which could be stopped reduced by bleaching your containers before use, not using outside soil, and using some kind of anti-mold/fungus solution. That might be the soft stuff like camomile tea and cinnamon, or the hard stuff like Captan. Google damp off disease for lots of ideas to prevent it.

Personally, I use 6oz yogurt containers with holes for my cuttings, preferring to not loose space with gallons. My cuttings get bushy but not tall, and have a nice root ball I shake out at planting time. It's a touch small, growth being inhibited, but I can fit more under the lights and have more insurance that I won't loose varieties. I use half peat moss, third vermiculite and a sixth perlite, with a pinch of lime, and wet it with hot water with a drop of non-antibacterial dish soap as a wetting agent.

Hope this helps.

Oops, sorry for butting in, Ted. We cross-posted.

No rooting hormones and no fungicide in our process. We soak the pots and flats in a bleach solution to ensure that here are no fungus spores. Rooting medium can be germination mix sold in bags(we use this) Oasis cubes, Rock Mineral cubes, Perlite, vermiculite, sterilized sand, and even one person uses his own garden soil that that has been sterilized by putting a pot of it on his very hot wood stove for a long time.
Humidity can be maintained by the use of plastic bags(our method), plastic domes, regular misting(commercial greenhouses do this). The plastic bag has the advantage that you do not have to check them or water them for the rooting period of about 12 days.

Thank you all for your great feedback!! So helpful! My containers have all been clean, the used ones dipped in bleach. I think my problem might have been temperature. I have now gotten a thermostat for my mat and placed my cuttings on it set to approximately 72 degrees. CCvacationand teddahlia, do you both use artificial light and for how long? Steve2282 mentioned about 15.5 hours for his. Some of my tubers have up to 8 active eyes! So if they actually sprout I want to take cuttings.

I love researching, and am constantly rereading articles and picking people's brains about their experiences. The top article I'd recommend is listed below. It goes into how long to light, and I've found it very useful. I light for 15hours based on the rationale outlined in that article.

You had not mentioned if you have a light setup yet.

Assuming you haven't as of yet, there are four options that come to mind:
1. just wait until last frost then stick the tubers in the ground
2. pot up or make cuttings, and use a window sill
3. use four foot fluorescent shop lights on a shelving unit
4. Use a grow tent with fans, exhaust and Metal Halide (MH) and High Pressure Sodium (HPS)LED lights

I'm sure there are other viable options, but 1-3 are the most common. The #4 is probably the best, but can get very expensive, and these setups are often found on...mmmm.... Well, google it and you'll see.

I use three sets of shop lights, and should probably go to four sets.

Hope this helps, as solutions vary greatly for the individual.

Here is a link that might be useful: Grow lights

I read the article and disagree. Florescent lights should be left on 24 hours per day. My theory is that the more light the better. In Alaska, the 24 hour light is famous for larger plants. Also, in my unheated space they provide enough heat to get the area up to the 70 degrees or so needed for rooting. I am just rooting the plants. That process takes about 12 days. When rooted they go into a greenhouse with only sunlight. So the short time that they are forming roots, in my opinion, has no effect on tuber formation later on. All evidence quoted is very weak anecdotal information. Tubers from plants grown from rooted cuttings are constricted from growing in a pot and are more difficult to divide. And to quote Phil Mingus, "Two or three tubers from a plant grown from a cutting is a lot better than none if you do not take cuttings."

Ahh, to have a greenhouse... I should get one some day, but im afraid of frying all my plants in one day of unmonitored heat. (A new gardening lady recently baked all her sprouting seeds that way, and was desolate for days.)

So after 24 hour lighting for 12 days, you put cuttings on a schedule of around 12-14 hours natural sunlight in the greenhouse.

Well, I suspect you're right in general with continual lighting might speed things up a bit. Honestly, it just doesn't seem to matter too much as long as the plants get enough to green up, unless you need the heat from the light or you're trying to hurry things up..

Was it you who mentioned how the Dutch make cuttings in complete dark, to make long sprouts from clumps? I cant remember all of it, but didnt they root them in dark, too?

Fascinating display of how versatile this species is, and how many ways there are to accomplish the same thing.

but didnt they root them in dark, too? No, I believe they root them in a greenhouse.
Greenhouses: They can be the best thing that ever happened to you but you must be prepared for the fact that the sun is your friend and your enemy. A greenhouse can heat up to unbearable, plant killing temperatures in just a couple of hours of intense sun.

Going back to my original posting, I've continued taking cuttings over the past several weeks and despite covering the eyes on many mother tubers it has been rare to find a sprout which could be separated along with an adventitious root already growing. I've found a few more sprouts like this and these cuttings do take off much more quickly (as one might expect) than the rootless cuttings but unfortunately I haven't found them with any regularity.

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.