Five children, all of whom reached child producing age. Admittedly my middle sister and I haven't started. So far I have nine nieces and nephews. A growing population will need a lot of food, so being farmers would be of tremendous help. The first generation would be people who lived on ships, perhaps for years. These would be the start of the Romulan technical society. Passing knowledge would be a priority. Their colony might be like when a new community is started here, investors and contractors cut a road into virgin forest, build 100's of homes. Local businesses build a grocery store a few gas stations and a shopping center. Instant community. They didn't suffer from a lack of supplies, the food was destroyed by fungus. And nothing says that this, or something like it, didn't happen to the Romulans. Descendants of those people who originally came from Vulcan. People who would spread outwards from Romulas. Colonization or invasion, people who built the Romulan Empire, who went to spend the rest of their live on some new world. Then, after a half dozen generations, their prodigy would spread to yet another new world, new colony. And after a half dozen more generations, the "children" move outward again.