Greenhouse for cosmos seedlings.

mchua

Hi, I’m transplanting some seedlings. To save room in my house I was going to use the geeenhouse instead. It is warm in there I don’t have any greenhouse sheeting at the moment to cover from direct sun. 

Will it be too warm for them? Shall I stick to the windowsill for the time being?  First time growing them.

Ty

AnniD

Have you got an old net curtain or something like that ,that you could use to shade them ?

WonkyWomble

Mine are in the greenhouse,  I leave the door wide open and window on vent

Butterfly66

I’ve don’t worry about shading until late May, early June. I’ve got automatic vents but also open the doors if the forecast is warm ( ignore wind chill/feels like temperatures, go off the forecast high)

mchua

Thank you very much.  I moved them to the greenhouse and they seem fine.  I leave the door and it’s only window open and close them at night. 

mchua

Although some of the seedlings fall over at the base, it’s not damping off, they just fall over because they’re tall. Even after transplanting into their own pot it’s tricky to keep them upright. Is that to do with light levels?

AnniD

One trick when you're potting them on is to bury them up to , or near to, the lowest set of leaves.
Also you need to keep turning them so that they keep returning to the upright position by facingtowards the light.
 I also gently brush the top of the leaves which in theory strengthens the plant.

mchua

AnniD said:

One trick when you're potting them on is to bury them up to , or near to, the lowest set of leaves.
Also you need to keep turning them so that they keep returning to the upright position by facingtowards the light.
 I also gently brush the top of the leaves which in theory strengthens the plant.

Thanks, and yeah I saw that brushing trick on a YouTube video, it’s the Project Diaries guy. 

mchua

Hi, they have been in the ground now for almost a month and have some nice flowers and buds coming through.  They’re only around 30-40cm tall.  

Do they normally take quite a long time to reach full height and spread?  Seems to be very slow growing. 

borgadr

I wouldn't worry too much.  My seed-grown, greenhouse raised cosmos were planted out weeks ago and are only around 30-40cm, like yours.  They're "Purity" and "Rubenza" and they're in a variety of positions - drier, damper, full sun, part sun..  This early they still have plenty of growing to do, even if they're starting to flower (don't forget to deadhead).

The ultimate size depends on the variety.  Some like Xanthos stay quite small.

mchua

Thanks yes I keep an eye on spent flowers and deadhead. I also pinched out the main stem early on which felt kind of brutal but I can see why now because they’re getting nice and bushy.