There is a shop in Berlin where you can mail order from.
I used to go there, moved some time ago and have not found a shop like that yet.

They do have "high P fertilizer",
Perhaps that helps,
Keep going with your great container garden,

Bye, Lin

Here is a link that might be useful: Fertilizer Hakaophos rot

Hi there,
about the cutting off:
I would risk to let a first light frost go over them, it really depends on the weather forecast.
I dug some of mine up in early Octobre, just to stagger the workload, and those bulbs shriveled badly.

I had a small window box with a short Dahlia sitting around for a while completely dry, around October, I meant to chuck it all into the bin. When finally getting around to emptying the window box I found a nice firm tuber, the dry spell seemed to have helped.

about dividing, not sure whether I understood you right:
did you plan to just keep them in the container and grow in the same pott for the next season?

You could probably store them in the pots, but I would always repott, making sure there are no critters or funny bugs eating away at your tubers.
And often parts of the tuber, the "old" original bulb, are spent and rot.

It would probably work to grow without dividing fot 2 years, but in general Dahlias tend to be more free flowering if planted as divisions, really old large clumps produce less flowers.

(BTW what kind of potting medium did you use?)

bye, Lin

I was going to either- 1. dig up, divide, and store in peat or 2. leave completely alone in their pots.
Since we are supposed to have a lot of rain in the next two weeks, I am thinking they'll need to be lifted and stored anyway because the pots will be super wet.
First frost is projected to be in late October. Several of my plants did not handle my vacation well(pet sitter is not skilled in plants...) so I am planning on fertilizing more often until then, poor things.

They're in about 60% sifted potting soil, 10% sand, 10% peat and 20% horse poo and shavings. I am planning on retaining most the potting medium and adding more poo and keeping it in larger tubs in my basement as well, so that it's even more broken down and "ready" for potting next spring.

Hello,,has anyone had experience with wintering dahlias in the ground in zone 6.?. I live in eastern pa and am wondering if anyone has wintered dinner plates in the ground...they are in a protected area and my dahlias all expired after I dug them up last year..ant help would be appreciated..
Thanx
Nancy

This post was edited by roxy_grower on Mon, Sep 22, 14 at 21:08

I'm in western pa, and have yet to successfully overwinter dahlia in the ground after trying several different beds. However, a gent an hour south of me has a semi-protected clump that he left in to rot, and it keeps on coming back for two years now, even through last year's freezes. Neither of us took any special precautions.

When trying to overwinter them in ground it is important to keep the clumps dry and insulated. I've heard of tar paper over the ground working, as well as tarps with leaf mulch on top. Typically the random success stories in the colder zones have the clumps near a foundation, which protects them, and provides drainage that was put in place for the building (ie, French drains, or graded ground away from foundation).

Personally, I wouldn't leave any cherished variety in the ground overwinter, but if you are okay with losses while you experiment, that's perfect.

I dug up my dahlias last week and put them in the basement in vermiculite for the winter. I didn't have as many containers as it turned out that I needed, so some are still in the open air. I bought another container, but the tubers are now shrivelled. Most info on shrivelled dahlias seems to refer to Spring time. What should I do to put my shrivelled tubers to bed? Should they be soaked to get some liquid back into them? Should they be put away even though shrivelled? They were beautiful this year, and would hate to lose any of them.

Usually a spritz with a water sprayer (like people use when ironing to damp the clothes a touch) is more than sufficient.

Mine wrinkle a bit every year (I just checked, they're wrinkled a bit) and make it through fine--but most of my varieties are tough as nails to begin with.

I've always dug mine in the Autumn, but in 2013 neglected to dig my sister's ( downtown Hamilton, Ontario - 6b, in a sheltered spot). Even though last Winter was VERY cold and harsh, her dahlias came up beautifully. I've deliberately left hers again... Worst case scenario - plant some of my extras if hers don't come up.