Hi Heather
I also plan on planting sunflowers this spring. As this is my first experience WS and growing things from seed in general I was looking up information online. I don't have an answer as to when you should WS them ... however I read that sunflowers don't like to be transplanted. The advice given to anyone who wanted to sow them in advance was to plant the seeds in pots that could be planted directly into the desired planting spot. ( ex. peat pots or newspaper pots) This would lessen the chances of losing your sunflower seedlings when transplanting.
Again I have no first hand experience. Maybe someone with experience can enlighten us both as to whether this is indeed a good idea or not.
Seems like it to me.

I usually w/s mine mid April..here in Southern Ontario. I transplant them quite successfully once they have their first set of true leaves. If you're gentle prying them out, they do o.k.
My problem is keeping the wascally wabbits and squirrels away from the newly planted seedlings. I put re-use centre freezer baskets over them until they get established, (and the clover is up!)

Mid to late April is good for sunflowers. You don't want them up and growing too early because they can freeze - voice of experience here. :)

Thanks ladies for sharing your insights. This is very helpful.

I planted 'pacino', and 'starburst' last year, in plastic beer cups, the pacino was 6" tall- 8" tall by the time I put them outside, and the starburst was a good 18"-24" they were rootbound as could be but transplanted beautifully, and produced multiples of flowers. The pacino got about 24" tall (as it should) and the starburst was 4'-5'. I took seeds from the pacino last fall and started them about 2 weeks ago they are very compact and have about 6 leaves on them, I don't know if pacino is a hybrid or not so I'm not sure what they will turn out to be. germination rate is excellent though so I am keeping my fingers crossed!!

I guess I should say... they weren't 'wintersown'... but they did transplant really well !

Can anyone tell me when its best to start sunflowers in my part of the country? I'm in northern Alberta, thanks

I w/s mine in late Feb. and they are up now. The past few days we have had snow and colder temps but they have survived. Marg