Citrus grown from seed has a fairly long juvenile period, so it can take about 7 to 8 years for a tree to flower and potentially bear fruit. They grow best in subtropical and Mediterranean regions up to 35 deg S or 35 deg N and are frost sensitive. In places like Great Britain and New Zealand, species can be grown from seeds as house plants; under favourable greenhouse conditions flowers may be produced but a termperature of 18-24 deg cels is required for fruits to mature. Also, to produce fruit, they require a cross pollinator.