Most MG's are fast growers so you can do either. If starting them indoors make sure you have adequate lighting until it's warm enough to put them outside. I soak my MG seeds in water overnight before planting. Many will germinate in a day or two. If they don't have enough light while inside the vines will get leggy and weak. A word of warning about Grandpa Otts, it reseeds like crazy. I planted some several years ago and have been pulling them out by the bagful ever since.