Tips on growing Cosmos from seed please

[S3agr0v394686]

I always find my efforts aren’t as good as seedlings I buy.

Sow seed.
They grow.

They are such easy seeds to grow, and they germinate so quickly. Mine were showing within 36hrs last summer.

I get them to germinate but they look pretty spindly and pathetic compared to garden centre when ready to plant out .Don’t flower as much.

How do you sow them? Deep 10cm pot with say 5 seeds in there, or small plugs?

I start mine in a propagator on the window sill and plant out after the last frost when the are getting their second set of leaves.

Do you pinch them out? It's the hardest thing in the world to do, but it makes a big difference to their bushiness and flowering.

Do you pinch them out? It's the hardest thing in the world to do

It's dead easy! Do you mean psychologically hard?

Once you have them let them self seed towards the end of the summer. I just move my self seedlings around a bit and position them where i want them. Agree with others who say pinching out is good - ie pinch our central stem.

My white ones grew well from seed last year but my tip top picotee seeds didn't germinate for some reason. I grew about 20 different types of seed last year and I think 2 didnt germinate. I think one was candytuft and the other was the picotee cosmos

Cosmos are usually pretty straightforward. First off sow think my, the seeds are large enough to handle so if you are using modular trays then 2 per cell is good. Agree with pinch them out. Once they have a few pairs of true leaves nip them from the top. This promotes bushy growth :)

Agree with dreaming. Let them self seed towards the end of the season. I haven't planted any for about 4 years, they self seed easily and I just move sturdy plants to where I want them in the spring. ( Unlike the borage which I just pull out and compost, rue the day I sowed them)

Only if you’re in a warmer part of the country. Not if you’re on heavy soil that stays wet all winter

@MereDintofPandiculation
I garden on very heavy clay soil, and it's well below freezing this morning, . Although my cosmos patch is south facing .

Pinch out. Plenty of light (wait a while)

Everywhere’s well below freezing this morning. Are you in the North?

They won't flower until the days start getting shorter (apparently) so there's no real advantage to early sowing - it won't mean earlier flowering. Wait until there is more light and warmth to get them underway.

I do find they can be temperamental - some plants romp away while others from the same batch sulk - they don't die but they barely grow. I do love Cosmos though- especially the Cupcake ones. There's no need to sow them early I agree, as they start to flower late.

Yes, obviously 🙄

As well as pinching out the seedlings you can make them a lot sturdier by burying the stems deeper when you transplant them. This makes a massive difference to the quality of the plant.

Don’t leave them in their pots too long. Get them planted out. Otherwise I find the roots never really set off on adventures and they remain spindly. so don’t sow too early.

As already mentioned, pinching out is essential, as well as regular dead heading. Shop bought ones will have been fed copious amounts of nitrogen feed, which is why they get big so big and blousy.

I am very lazy with Cosmos and just sow direct into large pots on the patio and then thin out the weedy looking ones. If I've time I move the thinned ones into other locations around the garden but they never seem to be as happy as the ones sown direct into the big pots.

I’ve found them easy directly planted them out or self-seeded. Any that I’ve tried to do early inside have been rubbish.

What time of the year do you do that? I don't have space to sow indoors, but would love to try some from seed.

@ChardonnaysBeastlyCat once it's warm in spring - April or early May I think.

Same, sow direct into large pots when we're safely past last frost. I'm in the NE and they're normally one of the last things to start flowering so I tend to bung some lobelia or something round the edges to make it a bit more interesting until they get going.

Thanks!