[Gardener and Rabbit]

One bedding plant I always struggle to get going are the red salvias, grown from seed.  At the moment they're sat looking small and a bit yellow-leaved once again, amongst healthy-looking french marigolds. I can't find online that they have any particular special requirements, and they've had a couple of feeds with liquid tomato food along with all the other bedding plants. They do eventually seem to get going, but are on the small side and late. Does anyone have any growing hints or tips?

G&R