when is it okay to put out zinnias started indoors

I normally think of putting out my zinnia seeds when it is much warmer, but this year I started my plants indoors mid-January. When do you think it is safe to put them outdoors? I was thinking maybe March 1 b/c that is our supposed last frost date. Thanks,
Annie

Not in Austin but as you have had some lookers but no responses, I am bumping this to the top. Maybe someone with knowledge with chime in. Best wishes... pod

Anniejo, I think March would be a safe bet. If you get any late frost just throw a sheet over them. Last year mine had started to germinate when the Easter freeze hit and they pulled through it.

Our last frost date in Houston is March 22nd.

I'm right down the road from you in Bryan and we had snow last April for one day. I would opt for the blanket too. I get them at the dollar stores. Anything will survive under a blanket :)

Are you sure, Gymgirl? The average last freeze date in Montgomery County is March 6, and we're north of you. Of course, last year we froze two weeks after. I did say average.

blanket - I set my zinnias out spring break weekend - with most of my veggies and they always do great with a blanket if old man winter comes back. Everything else goes out on Good Friday - love the symbolism there too... and it is the old time way to do it.

March 22nd is after our last frost date in the Dallas area too... that feels really late for Houston...