Karen, everything I've read about starting salpiglossis from seed indicates that they really want darkness to germinate. I put a piece of cardboard over the flats in my GH. But once they germinate they need light and cooler temps (persnickety little snots). You might try putting your jugs in a shaded spot or drape some shade cloth over them. They're such striking flowers, I think they're worth a little fussing with.
The volunteers I got all came up in areas that were shaded.
