The term "Pot tuber" was new to me too this year

Pot tubers are most often used for propagation - taking cuttings.

Here is a quote from another site and a link to a different article.

"teddahlia wrote:
Pot tubers: If you were a really an old geezer and disliked digging and dividing tuber clumps, you could avoid doing so by the use of pot tubers. Step one is to take some cuttings from the tubers(or pot tubers) that you saved from last year. Instead of planting these cuttings in the garden, you leave them in the 4 to 6 inch pots and grow them in a dedicated small section of your garden. They can be left on the top of the ground. They take up very little room. They may or may not bloom and if you really want them to bloom you would give them a bit of fertilizer. You go ahead and plant your main garden and enjoy your plants as usual. Now in the Fall instead of digging your plants in the garden you leave them there to freeze. You harvest your pot tubers before the first frost by removing each plant from it's pot and store the pot tubers like you stored tubers. That would be in plastic bags with some vermiculite if you would do it like most people. And in the Spring, you would take cuttings from your pot tubers and plant some of the rooted cuttings in the ground and leave some in the pots for the next year.

Harvesting the pot tubers takes about 10% of the effort to dig up dahlia clumps and divide them. Yes, there is some more work in the Spring taking some cuttings but that is easy work compared to digging and dividing dahlias. I first read about this growing technique in Phillip Damp's book on dahlias. He lived in England and over fertilized his dahlias with copious amounts of cow manure. He claimed that because of the six inches of cow manure, that the tubers would never store if you did dig them. Thus he grew pot tubers of everything he wanted to grow the next year."

Here is a link that might be useful: pot tubers

Thanks Mandolls

I figured either you or Ted would know and it looks like I got the Daily Double!

I began to think that some of the dahlias I've had in pots that never grew were because I didn't look for 'pot tubers' .But that seemed odd so I had to ask.

Thanks much.

"He lived in England and over fertilized his dahlias with copious amounts of cow manure. He claimed that because of the six inches of cow manure, that the tubers would never store if you did dig them. "

Why would the cow manure/heavy fertilizing affect the storage/dormancy period of the dahlias?

I actually was wondering about fertilizing, because a popular blogger I follow who grows a ton of dahlias for cutting uses the heavy bloom Miracle Grow (something like 10-30-30) on hers and swears by it, but I wondered if this might affect the 'longevity' of the tuber, aka similarly to say a tulip where if you cut the majority of the stem and leaves then the bulb might not put a flower out til 2 years. But since dahlias are not like tulips where they just put out one flower I didn't know if this was relevant at all.

So, curious to hear/read about the fertilizing, can anyone offer thoughts? If I end up heavily fertilizing would it mean my tubers wouldn't be as robust but more 'tapped out' for next year?

Dahlias need nitrogen to grow but an over abundance of nitrogen late in the season causes the normal looking tubers to rot during storage or in the ground if you leave them there over the Winter. Varieties that make smaller or difficult to store tubers will rot a lot more than abundant tuber makers. The rule of thumb is to give dahlias the nitrogen in the first half of the growing season and stop applying nitrogen about 60 days before digging time. You can use some fertilizer with just phosphorus and potassium anytime and commercial growers do so about 30-45 days before harvest to plump up the tubers. If you checked the mineral content of a dahlia tuber, the majority is potassium so they need that and phosphorus to get some size.

That makes sense, thanks!! I also read another dahlia grower mention not to use cow manure so I didn't quite understand what the downside was. Her tubers are HUGE at the end of the season so she must be doing something right.

Huge tubers would be great if you are growing them to eat. Experienced dahlia growers shun overly large tubers as they do not grow very well. Medium sized tubers are best, about the size of a hen's egg or perhaps slightly bigger. Manures are excellent products if used during the first half of the growing season. Phil Damp was an exhibition grower who over fertilized his flowers on purpose. He won many prizes with them. He knew that by using so much manure that the dahlias would produce excellent show flowers but that any hopes of storing the tubers would be futile. He grew another garden where he put tubers or rooted cuttings into 6 inch pots and gave them almost no fertilizer. These small tuber clumps were used to make rooted cuttings for his show garden the next year.