Stunted growth:

you mentioned in another post that you had water drainage issues. I have lost a couple hundred tubers due to the same thing, but was able to help the remaining tops to root from the stems by replanting the tuberless greens deeper in mounded rows. Many of them are under two feet right now, and only thinking of blooming. It's possible that yours did the same thing, and just rerooted on their own. They might be putting their energy into their roots instead of their blooms.

Fertilizer:

Right now your dahlias should be working on maturing their tubers for dormancy. I would be cautious about fertilizing much at this late date. Many growers have told me that late-season fertilizer (especially nitrogen) is stored in the tubers and can cause rot overwinter.

Lots of show growers keep potroots or a secondary patch that they don't fertilize after August to get the best storable tubers.

.Perhaps a foliar spray with magnesium (Epson salts) and basic formula will kick start your beds without overdoing it. That is what I've given mine, as root formation is more important to me then bloom production this year.

If root formation is not as important to you, dose it liberally with whatever you have, making sure magnesium is included to help with the absorption of the nutrients, and it will likely help with top growth.

Thanks cici you are a wonderful wealth of dahlia information. The owner of the estate that I work on always buys new tubers she is kinda like a kid in a candy shop, and who can blame her. So most important is lots of blooms for the next two months at the expense of the tuber. Can you advise me on how to make a foliar spray with Epson salts?

If that's the case, I'd sprinkle a tablespoon of Epson Salts per plant at the root zone, then hit it all with a good drenching of 20-20-20 MG connected to a hose, being sure to soak the Salts and roots thoroughly. I'd make sure to wet all the leaves, especially the bottom of the leaves. I'd do the Miracle Grow every week until progress is made, followed by every other week.

You could do a foliar feed of Epson salts on just the leaves with a pressure sprayer every week , but I would've add any more to the soil after the first tablespoon. For every gallon or so of water, mix two tablespoons in a couple cups of very hot water, dissolve them and add a squirt of dish soap as surfacant (be sure you add soap at the end of filling the pressure sprayer to avoid suds!)

Again, this is what I would do if performance outweighed long-term considerations... Every grower has their own strategies and opinions.

One long-term consideration is what you are doing to the soil by overloading right now. There is no easy fix to satisfy every consideration.

Your last point is a very good one cici. May do a foliar spray thanks for the information.

I have done a foliar spray most of the summer and have feed the dahlias with an organic fish emulsion three times and with a bloom booster( high in P and K) that my owner sent me. Next year I will not do the bloom booster do not think it is necessary and even wonder if it may have done some harm. I like having my dahlia tubers winter over and last year I had about a 80 % success rate. In the spring I saved about 50 tubers for the owner and gave hundreds away to friends I felt like Santa! I do know how to grow dahlias and most other plants but I am always learning more and more that is what I love about this business. Thank you for my continuing education of dahlias. Lynn

I thought I remembered you being well-informed, but I don't always trust my memory. Thank you for not taking offense at my over-simplification.

If you haven't already, this season might be a good excuse for you to suggest a lab soil test to your employer, Lynn. It would better prepare you for what nutrients are lacking or is overloading the soil in the dahlia beds. The local university extension office can normally set you up with reasonable and thorough tests, and often have knowledgable folks on staff to explain any results.

My lab tests had me cutting way back on fertilizer, emphasizing on consistent watering and foliar feed instead. I am dedicated to correcting the soil pH, that is adversely effected by some fertilizers. Apparently I was slowly poisoning my soil with too much, even though I thought I was applying it lightly.

Yes that is a good idea I should get a soil sample and will this fall. Thanks. Lynn