Experts and BHG readers answer.
Not sure if you mean from seed, or the plants. For plants, fall and spring are always a little easier because the weather is less stressful to plants as they become established.
By seed, you can put them in the ground in fall and see what comes up in spring. Or (my preference) plant them indoors on a sunny sill or under a flourescent light, and then plant the plants outdoors in spring. They'll germinate much better if you scratch the seed a couple of times with sandpaper before planting.