Where are you based @newtogardening?
Generally you don't plant them at this time of year. You plant them in spring or early summer. Then they only take a few months to mature.
I realise this is a bit of an old conversation, but I was hoping someone might know whether its too late now to plant some sunflower seeds?
It's never too late to join the discussion @Salfred, although it might be too late to plant those seeds. Hopefully community members with green thumbs like @QuailFlock and @greygardener can let you know.
You might also find this information from Bunnings useful - How to plant and care for sunflowers.
Let me also extend a very warm welcome to the Workshop community. We're really pleased you could join us and look forward to reading about your projects and plans. I'm sure you will learn a lot from our members and be inspired by their creativity.
That must be frustrating @Helen. Why do you think they are snapping off? Is it the wind?
No, sorry should have said eaten flower heads & chewed off just below flowers, cocky damaged! Is frustrating, was waiting for a great display.
Have you tried anything to keep the cockatoos away @Helen? Perhaps a kite or some fishing line across the area?