Got any tips for collecting petunia seeds?

[sepeters]

I have never grown petunias from seed before, so bear with me. I am totally ignorant.

Believe it or not, last spring was my first time ever growing petunias. I purchased several trailing varieties as seedlings and placed them up on window sills or hanging in baskets. All of them died in May, except two kinds. One is a royal velvet (dark purple) and the other is white, but I don't know the specific name. I transplanted them both into a window sill container and have coddled them, and they have thus done very well. Both plants hang down maybe about 3 1/2 feet at their longest point and are very tangled up with each other.

For a while I was maintaining them impeccably, but have been so absorbed with the vegetable garden lately that I was not properly deadheading. Well, now there are petunia seeds spilling out all over the place and the purple plant appears to be dying. The white one seems to be ok and because they're so tangled up I can't tell if it is going to seed.

So, a couple of questions:
1) There are little itty bitty petunias popping up in my potted veggies under the sill. When should I dig them out and transplant? Most have only their seed leaves or their first set of real leaves.

2) What's the best potting mix for petunias? I don't think the veggie mix I made will be good for them, as it has lots of manure in it. I am willing to make my own mix or buy bagged. Doesn't need to be organic, but that would be a plus.

3) From doing a forum search I read that most petunias are hybrids. What can I expect from these new plants? Will they have further hybridized from being so close? Or am I more likely to see them reverting to the original, non-hybrid varieties?

4) How should I collect/store the seed that is stuck to the plants (the leaves are very sticky and have tons of seeds all over them!). So far, I have been cutting away sections that are wilted and left them in a container in the sun to dry.

5) Any possible reasons the white petunia is not going to seed and dying? Not that I want it to die, but if it going to die I'd like to get some seed from it, as well. Just wondering if there are varieties that are sterile...or something.

Thanks in advance for your help, guys!

[sepeters]

Oops! I meant to post this in the "flowers" section! Could one of the mods pretty please move it for me? Thanks...

[cynthia_h]

moved per OP's request.

Cynthia H.

[rainbowgardener]

Yes, some of the hybrid varieties are sterile. I grow double petunias (as well as single) and the doubles don't set any seed at all. And yes, when you grow out seed from your hybrid petunias, they do not breed true. The next generation will still be petunias, but may have some colors you didn't have before, sometimes even stripes or markings. To me that is fun, see what results. I have found growing out generations of seeds, over time they tend to get paler and eventually white. I'm thinking the ur-petunia may have been white. But that only happens over several generations; your first generation from seed will still be colorful, just not exactly the same as the parent.

I wouldn't try transplanting any of the seedlings until they at least have true leaves, maybe 2 pair. Then move them into a nice light fluffy potting soil mix.

[sepeters]

Thank you RBG! I am excited to see what kinds of petunias come from the seeds! They are growing slowly, but are almost ready for transplanting.

I left the dead plants out to dry because they were covered in seeds, but am still having a hard time getting the seeds off. In the future should I cut the terminal end that produces the seeds off after I dead head the flower? Or is it better to leave them on the plant to dry?

[rainbowgardener]

Not following. If you dead head the flower, you won't get any seeds. The seeds develop inside the flower and are not ready until the flower has died back.