I haven't grown it from seed, but I have grown it as an annual purchased in probably 5 inch pots. I never tried to keep it through the winter as I had the idea it would not make it. Lowe's sells it in summer.

I saved a few seeds one year and winter sowed them but only got one seedling. I planted it out and it waited to bloom until very late in the season. The butterflies were already gone. This year, I found a volunteer but it didn't do much either. I don't know if I just had bad luck or if it's one that needs to be started early.
I think I will stick to buying them in pots. I've had better luck with that and they grow quickly. A person could most likely winter those over in a garage but they get pretty big sometimes even in just one season so it might not be worth the trouble.

I love lantana and here, they grow like wildflowers all year long and get as big as small bushes. In MO, I always had them, bought in pots every year and that was the only way I could find to enjoy them. I tried one winter to keep it in the house, but I think they are purely humidity lovers, and the furnace air all winter was just too hard on them ... and I was probably not diligent enough in giving them the moisture they need. Leaves dropped like crazy until it was just twigs. Maybe I was a poor nursemaid, but after that, it was just easier to keep buying new ones in season....

I think they are too slow to grow from seed here.
I never had much until the end of the growing season as well.
I tried to bring in one year and kept it in the bathroom.
low/med light and moisture. didn't need to water very often. I had cut it way back to start with. By spring it was looking sad. but did make it.
Decided to just buy new plant each year.
Bonnie

I tried growing Lantana as seeds and it was not sucessful. I had very poor germination rate. It could have been the seeds though, but the next year I bought potted ones from Lowes. You could try starting your seeds inside early spring and planting them outside later in the spring. I planted mine into the ground. The one or two that did made it did not bloom.

Have grown lantanas here in Z6 several times and found i'd lose them about every 3rd year due to a long hard freeze.