I am planning to start some of these from seeds for next year's garden. Somewhere I have heard, or read,--- that they require a chilling after germination in order to obtain flowers.
I can not find the reference. Does anyone know?

Hmmm, in growing Osteospermum from seed in the past (I admit I haven't grown a lot of annuals in a long time), they performed normally without having to grow the seedlings in any sort of cool conditions... ?

Could be the cooling is for growing in warmer climates,
and here they will be cooled when transplanted outside anyway.

I did read one entry that said, during periods of hot weather, periods with cooler nights promote better blooming... ?

It fits Calgary!
They are native to South Africa.
When I grew them before, I had purchased plants which were already blooming.

been a while for me as well.. don't think I chilled the seed.. but they are slow growing.. never reached blooming size for me.. some were real late in fall.. gave up trying after the 3rd time

I think that it was the plants which were to be chilled, but can not find it now.
Here they are likely to be chilled when planted out in the spring.

It's been several years since I've grown these from seed, but I don't recall any special treatment of the seeds or plants. They did take quite a while to bloom, though---rather late in the season for me.

Thanks for your comments.
We shall see next spring.

Please keep us posted, Caroline. I find it fascinating how our differences in zones can affect our processes.

Linda

I did a lot of searching, and couldn't find any references that suggested the seedlings need chilling... ? As I mentioned, I found one entry that said that blooming plants slow down their flower production once it gets very hot, but may resume if cooler nights come along, but this didn't seem to refer to seedlings. Given that osteospermum are commonly grown, one would think such a recommendation (i.e. chilling the seedlings) would not be obscure, if it was quite important?

Yes, I shall just do them the same as any other bedding out plant.

That's been my experience: they just don't tolerate our heat very well. They survive but don't thrive.

I only grew them from seed once, and that was by wintersowing. They did OK in spring, but once the summer heat and humidity arrived they stopped flowering and I could barely keep them alive

Karen

A winter sow-might try that too.