They will do better if you wait until warm weather. They really love the heat and sun. You don't have to start them early because they grow fast. It is time to start petunias which have tiny seed and take a while to grow.

You can start them indoors if you have the space and enough light, but as Helen says they grow fast, so you can simply direct sow them after your last frost. They transplant very easily so if you get them too thick, you can move some and water them in well and they will take off.

They do cross pollinate, but I have never had that problem with the ones I've grown, and I've grown several varieties. Either mine have not cross pollinated or the ones that are pollinated by a different variety as not as strong or vigorous as the original parents, and do not come back as a result.

A way you can reduce the amount of cross pollination is to grow them in groups. For instance if you have seed of Scarlett Flame, sow your seeds in one location, and then sow your seeds of another variety altogether in another location. It won't guarantee that there won't be any resulting hybrids, but it will reduce it somewhat. In order to completely eliminate the possibility, you would have to plant each variety 1/4 mile away from another, and that's just not possible in most backyard gardens.

I don't collect the seeds, but let them fall to the ground and a few of them come back. That way, I am always forced to add new seeds each year for the new generations.

A girl on the Butterfly Forum grew a very large mass of Scarlett Flame and her images were stunning! She had butterflies all over those zinnies!

Susan

But that didn't answer the question about starting indoors. I would count back 5-6 weeks from the last frost and start them then.

Thanks! I'll wait a few more more weeks.