The rooftop is a confirmed destination
The official Tiny Eden description frames the rooftop as the far end of expanding a small apartment garden. It is a progression landmark, not a separate platform, mode or confirmed endgame checklist.
Do not assume outdoor rules
Because light, temperature and soil are confirmed systems, a rooftop could matter to a plant’s environment—but the public sources do not specify how. Avoid copying advice that claims fixed rooftop bonuses, weather behavior or plant-specific requirements without a versioned source.
Use your current save to document it
When you reach the rooftop, take the in-game condition panels as the primary reference. A future revision can add exact behavior after it has been tested against a named game version.