Help please - my cosmos have all started producing flower buds at 6" tall

Christine-21

My cosmos bipinnatus 'Capriola' seeds dutifully germinated in February and started growing, and I potted them on at the end of March into 3" pots as recommended, but 90% of them started to form flower buds at only a few inches tall.  I pinched out all the flower buds, but the resultant side shoots have all done the same thing, and the little plants are sparse and leggy rather than bushy, and only 4 of the 30 seedlings are now ready to be planted out.  This variety is supposed to grow to 30", so they shouldn't be forming buds for another two feet!  What am I doing wrong?  Can I save them, and if so how?  Any advice welcomed.

Pete.8

I think you may have sowed them a bit too early. They're at an age where they feel they should flower.
I sowed mine this year on 4 April and they're now stocky plants about 10" tall (having already been pinched out) and if we get a break from the never-ending sun I can get them planted in the garden.
A photo would help if you have one.
Cosmos are pretty tough and will do their best to give you a long display of flowers.
I expect mine will start forming buds in the next week or so when they'll only be about 1ft. They will continue to grow and flower. Last years cosmos mostly grew to 5-6ft and flowered all summer.
I'm sure yours will be fine

Lyn

Gardening is always a lesson Christine, I also sow mine at the start of April and have good stocky plants to go out soon.  Make a note in your gardening diary of when to sow next year. In the meantime just put what you have out and see what happens, not much you can do about it now. 
You could sow a few more for late flowering they’ll be up in about 3 days. 

Christine-21

Thanks very much, folks, particularly for being so prompt!  I think you're right, I am always tempted to go buck mad in January when Christmas has all been put away, and celebrate with the seed catalogues... I have this daft idea that if I start things off early I'll give them a head start, but you're right, to everything there is a season!  And here's the proof:  one shy seedling emerged last week from a seed tray I'd left lying about (and threw some chilli Apache seeds into, from a plant I had last year, without much hope), it turned out to be cosmos, and today it looks healthier and bushier than the ones from February!   Next year I'll restrain myself till the beginning of April...  (and five or six wee Apache seeds have germinated too...  )

Pete.8

I was the same a few years ago. I'd sow tomatoes in January and by March they were so leggy they were useless.
As @Lyn says, a diary is very useful. I've started one (an Excel s/sheet) this year with the start and end flowering dates so I can work out next year how to have flowers all summer.
Last year's cosmos self-seeded and the little plants are 6-8" now. Really stocky and strong plants - tbh they're 'better' plants than the ones I've carefully sowed and nurtured....
Hoping your chillis and cosmos are a great success

Fire

Me too. I planted cosmos in March and carefully cosseted them on a windowsill inside - dragged them up to about an inch over the months (not enough good light). Then I whacked some seeds in a few weeks ago outside, thinking it was too late and those new seeds are now grown into robust, plants, bigger and stronger than the early plantings. It's a bit gutting, after all the work and careful inside watering. I also popped in some old sweetpeas too, in a spare pot, not thinking much of it, and, behold! they have romped away in two weeks and are much stronger than earlier plantings.   So much for planning ahead.

Lyn

There’s nothing like Mother Natures Own to get your seeds going, unless you’re sowing tropicals. 
My garden is bursting with flowers, I’ve never owned a propagator and wouldn’t want one.  Seeds that germinate at the right time are stronger. 

Christine-21

Folks, thanks very much for all your interest, sound advice and support!  I had this mad idea that if professional plant suppliers could bring their plants forward, why couldn't I, working between the warm kitchen, the west-facing living room which has floor to ceiling windows, and my unheated greenhouse (like Fire, with industrious moving things about and watering etc...)?  Well, the clear answer is, dunno, but you (I) can't!!

Can I offer another interesting (to me) conundrum?  I did an autumn sowing of sweetpeas.  I had too many seeds for the root trainers, so sowed half of them in a clutch of cardboard toilet roll insides that I'd been hoarding for months (like a mad old woman, come and see my collection of loo roll tubes!)  And some kitchen roll tubes cut in half, they're wider, but didn't perform any differently from the loo roll tubes.  Seeds from the same packets (I bought five different colours, because I wanted to know what I had got), and sowed from each packet in both containers, carefully labelled - I need to get out more), sowed in the same compost, on the same day, kept on the same kitchen shelf, moved together to a cooler room with better light once germinated, treated in all respects exactly the same.  They all germinated promptly, but over the winter and spring months the ones in the root trainers did literally twice as well as the loo roll ones - far more robust, lusher, stronger plants.  And they are doing twice as well now that they're outside.  I am wondering, is it something chemical in the loo roll cardboard, or indeed the happy fungus that colonized their outsides, that somehow stunted them?  My guess is that they'll all do as well, or at least well, eventually, and certainly will all make my summer a much more wonderful place; I'd just be interested in why the difference in their growth.

Finally, I'm not sure autumn sowings of sweetpeas are worth it.  They were garden-ready (even with pinching-out) before the garden was ready for them.  While I'm in rowing-back mode, I think I'll leave my sweetpea sowing till March next year.  That's what I did last year and time will tell if the summer shows any difference.  I'd be interested in what you think.

Fire

I found the same about loo rolls. I did an experiment this year, comparing root trainers and loo rolls and the root system was much better, healthier and more extensive in pots. My recent, spring, SP sowing have also done better than ones started indoors early in the year, but I don't have a good greenhouse. That seems to make a big difference.

Purplerain

I have found roots trainers to be the best. I once tried loo rolls years ago, but they never broke down properly.

I did some in March in pots and they are outside now, but the root trained ones from Autumn are doing better. I planted them up with my grandaughter in big pots with obelisks around February, but kept them protected. They are definitely the strongest and healthiest ones. 

I am not sure I would bother with the faff of that again though. A March sowing would be fine for me. They all flower in the end.

Fire

Feb? Wow - are they flowering now?