Dahlia tubers... when?

After some serious googling I now know I should plant my dwarf Dahlia tubers about 6 weeks before the last expected frost into a well warmed soil after all danger of frost has gone. Right. Please give some comments and suggestions. Also, which way should they be planted? They look like flattened octopuses, do the legs go down, up or sideways? It's 20 years since my previous Dahlia... Thanks for help!

 

20 years since I last grew Dahlias with my Mum too - so this advice is worth precisely what you paid for it

We used to put the dahlias tubers in trays of peat; the trays were wooden and used for fruit by the greengrocers - they had little wooden pegs in each corner so that when stacked they had a couple of inches gap between each tray; Ahhhhh! those were the days

The original stalk of the dahlia is upper most. The tubers themselves can't grow - they are just the fuel-tank for the stalk to grow - and it is from the stalk that the buds will break and shoots will form.

An old boy who was fanatical about Dahlias, and who my parents "cultivated" (sorry!) to encourage my youthful hobby (which, with hindsight, they must have thought manna from heaven compared to smoking or snogging behind the bike sheds!) showed me how he took cuttings from the shoots.

So, splay the "legs" outwards , pointy-stem upwards, and sit on a bed of compost 1" or so deep, and cover with another inch, or so, of compost, and they should start off just cushtie!

I do pretty much the same thing with my Gladioli corms

 

I had never thought about doing it with Galdioli corms Kristen - but it makes sense.

I would agree with Kristen. The principle is that you plant them in two stages. First you "chit" them ie get them into growth, then you plant them in the ground. To "chit" them, as Kristen said, you only half cover them in compost. Then let them bake in the sun. Warmth will tell them its time to get out of bed. The reason you do it this way is so that the crown (the woody bit at the top) doesn't get damp and rot. You need to give the compost at the bottom some water, but not too much until growth gets under way.

Once you get three or four inches of growth, the crown is no longer in danger of rotting and you can plant the whole thing in the ground, as deep as you like. Six inches would be quite acceptable.

There is an alternative method, and that is just to shove the whole lot in the ground and ignore the above. It will probably work 90% of the time. But the above method should be a bit earler and safer.

 

Just have to be a bit careful with the roots when transplanting Gladioli, and obviously not leave them "chitting" for too long!

 

I've got some Dahlia tubers potted up in the greenhouse, growing away nicely with a good 4 inches or so of growth, do I need to harden these off before putting into the garden?

I'm also growing some Dahlia from seed that according to the packet will flower this year, is this a different kind of dahlia or will the be tubers I can lift at the back end of the season, store and replant next year?

Steve...

 

Steve - yes, I think you will need to harden them off - but it may still be a bit early to put them in the ground. Whilst the last frost last year was about 23 April for me - we could still get a frost. Two nghts ago it was down to 0 C. Its a bit of a gamble - as always.

There was some discussion about Dahlias from seed a while back. I understand that they are essentially the same, and will produce tubers in autumn like any other Dahlia. The discussion was whether they really could produce flowers as early and for as long as ones from tubers. I would be interested to know. My gut feeling says that they should be better in a second year when they are grown from tubers. But at the same time I grow things like Salvia patens, which also produces tubers, and I think it is as good from seed (ie first year) as from tubers (ie second year).

 

Thanks Peter, I'll keep a record of them this year and next for comparison sake. and report back to GC in around 18 months time..:D

Steve...

 

"I've got some ... in the greenhouse ... do I need to harden these off before putting into the garden?"

I think even for this general case the answer is "Yes". Otherwise the plant will get a shock when you put it out which will either slow it down or, worst case, knock it on the head :(

"I'm also growing some Dahlia from seed that according to the packet will flower this year, is this a different kind of dahlia"

Is this what I would call "bedding dahlias", or are they the normal, tall, pompous-flowering type?

 

Kristen - I have just been doing a bit of research. You are right to distinguish between "border Dahlias" and "bedding Dahlias".

All Dahlias are essentially similar in that they are perennial plants that produce tubers, and all have been developed from the same few wild species. All Dahlias, of course, can be grown from seed. But, because they are all hybrids, seed usually produces inferior plants and it is only the exceptional rarity that produces the large "border Dahlias" that we know. Once found these are only reproduced therafter by cuttings (or by division).

However a range of small Dahlias has been developed, which are called "bedding Dahlias". These come true from seed ( or at least all produce similarly good offspring), and they will also flower satisfactorily in the first year. These obviously go on to produce tubers and can be grown from the tubers in the second yearif you wished. But the essense of "bedding Dahlias" is that you don't have to, as you can grow them from seed like an annual.

So on some measures they are all the same, but in other ways Dahlias from seed are different, in that they have been developed as a different type to be grown as annuals and are smaller than "border Dahlias".

 

Yup, that's as I thought. I just wonder whether Steve has gt seed for the "Bedding Dahlias" and if he's after the border ones he may be disappointed (my recollection is that bedding dahlias are short)

 

Thanks guys!
Anyways, I don't have a possibility to chit...cheat...chatter... whatever them in advance, I think I'll just have to splat them into the poorly prepared place I have for them. When should I do that? Tomorrow? (please say yes)

Sideways CE or upright? Which end goes up?

Thanks again!

 

Yes - its probably fine to plant them now. All the tubers are attached to a woody bit, which is the crown. And all growth will come from the crown. So stick the tubers at the bottom and the crown at the top. You can plant them reasonably deep. I have been told by the Dahlia society that you could even plant them 18 inches deep. but 4 inches is probably deep enough. It will take a little while before the growth appears above the ground by which time all frost should be well past.

Best of luck.

 

Just seen this thread. I you'st to grow bedding Dahlias from seed years ago. Sort of forget about them when planning the Summer borders, but they are dead easy from seed and produce showy, colourful flower heads on short stems, well worth the effort. They do produce tubers which will send up shoots the following year if they are protected from the worst of the cold, but I found that new seed each year worked better for me. Might have another go this year.

 

We grew our first dahlias from seed last year and the results were so good I'm doing the same this year too, I did collect some seed from the plants I grew last year and also some tubers too.

I must add I am also growing some seeds that I brought just in case the seeds I saved from our plants last year aren't too good...if you know what I mean.

The whole fun of gardening is to try to do some things yourself and not totally rely on brought seeds and swapping to me at least is another form of recyling and I'm all for that. :wink:Hel.xxx.