Dahlias - to pinch or not to pinch?

[Protea]

the dahlias i grew from seed are doing well in the greenhouse, but some are getting a little on the large side, particularly when they can't go outside for a while!

Should i be pinching out the tips to get more bushy plants, or just leave them as one stem?

Cheers to anyone who can help!

[Alice]

Pinch the tops out and you'll get nice bushy plants Protea. Also Dahlias are quite tough. You can't plant them til all risk of frost is past, but they will do fine outside in quite cool conditions and you get much hardier plants. I keep mine outside as much as possible so you could certainly start hardening them off.

[Protea]

Alice, thanks so much - i'll pinch the tips out as soon as poss.

I was worried they were frost tender but if they're not they'll be bunged in the cold frame henceforth as they're the blighters that are clogging up my greenhouse!!

[Two_Sheds]

I've got tubers not seed, and am getting a good lot of cuttings off them

[Protea]

I'm going to save any tubers that have nice flowers this year, and then do this cutting thing that Nick talked about a few weeks ago (its all a mystery to me this flower thing - now veggies i can understand!), so do let me know how you get on Two Sheds.

I've also got a few tubers i lifted last year that i potted up a couple of months ago just starting to sprout in the greenhouse - when is it safe to chuck them outside (in pots) to harden off?

[srodders]

How long after planting tubers should you expect to see shoots? And how long before you should dig them up as a waste of space and get something else in?

Mine have been in for 4 weeks and not one shoot - have the tubers 'gone off' or shall I wait longer?

Thanks.

[Two_Sheds]

I start my tubers off indoors, then cut off the shoots with a bit of tuber attached and pot up with a mini-cloche (cut down water bottle).
Probably 40% of my tubers don't shoot at all (dried out/dead), so its good to increase your stock with cuttings.

[Alice]

Alice, thanks so much - i'll pinch the tips out as soon as poss.

I was worried they were frost tender but if they're not they'll be bunged in the cold frame henceforth as they're the blighters that are clogging up my greenhouse!!

Hi Protea, as I said , Dahlias ARE FROST TENDER but they will tolerate quite low temperatures above that. If you harden them off you should be able to put them outside during the day on most days and in a cold frame at night with some fleece if required.
DO NOT EXPOSE TO FROST
You've got me worried.

[Protea]

Hi Protea, as I said , Dahlias ARE FROST TENDER but they will tolerate quite low temperatures above that. If you harden them off you should be able to put them outside during the day on most days and in a cold frame at night with some fleece if required.
DO NOT EXPOSE TO FROST
You've got me worried.

Ah, i see - well, i've pinched out 3 trays and put in the cold frame tonight, we're not expecting frosts but i will keep an eye on them and pop them back in the greenhouse if we suddenly get sub-zero's forecast.

so i should have read: cold tolerant but still frost tender

[Alice]

That's it Protea. Your Dahlias will be OK in quite low temps, but will not stand any frost. Once hardened off I find they are fine outside in temps down to 5 degrees overnight. In a coldframe with some fleece 3 degrees brings no harm. Below that - I don't vouch for.

[jools]

I have loads of these too. I haven't grown them before so I have a couple of questions please.

How big do they need to be before I pinch the top off?

Probably a daft question - Do the ones you grow from seed form tubers which you can then dig up and overwinter or are we talking about a different beast altogether?

Thanks

Jools

[nick the grief]

If you'd let them get a bit bigger you could have rooted the tops as well

Don't let them get frosted & will see them off in no time. As too tubers, I've just put one on my propagator bench and it's shooting (about 2 - 3 weeks) that said I've got two that have been on for about 6 weeks now and 1 is just starting to shoot and the other isn't doing a damn thing.

Try spraying the bit where the stem joins the tubers with warm water, it may start them into life but it could be that you've just got a "blind" tuber (no eyes to shoot - could be damage caused by snails or the likes)

And yes Jools, bedding dahlia's will form a tuber as well so if you have a particular colour you like you can save the tubers.

Also, if you let them set seed at the end of the year you can save yourself a few bob as well.

[terrier]

Hi , anyone reading this old thread? Although I've had lots of good plants from Dahlia seeds, I've tried with tubers for years and had very little or no luck with them. Problem is I cant get them to shoot. They just stay dormant. I've tried starting them off as early as February and as late as June in boxes of peat in a warm, airy room. The few shoots I do get, I pot up the whole tuber but get very little growth and usually no flowers. At the moment I'm trying to coax last years Bishop of Llandaf tubers into life. But so far, nothing. Is there a foolproof way to get them to sprout?

[chillie girl]

I leave my Dahlias in the ground. I have walls all round my garden so it is quite sheltered. So far Moonfire has sprouted also an orange (cant remember name) too, but still waiting for the Bishop and Roxy. Fingers crossed they will come up too, they were fine last year. Have grown some bedding Dahlias this year from seed, they were put in the ground yesterday. They have two chances, grow or not.

Tracy

[JennieAtkinson]

Thanks Terrier for bringing this one back on again. My dahlia seeds are doing quite well, potted on a couple of weeks ago and making quite nice plants now. I would need to know how "big" is big for nipping the tops too please. Mine wont go out for another 5/6 weeks yet unfortunately.