Rubber plants prefer well-draining, airy soil that holds some moisture without becoming waterlogged. A good-quality indoor potting mix combined with perlite or orchid bark can improve drainage and airflow around the roots. Choose a pot with drainage holes and avoid compact soil that stays wet for long periods. Repot your plant when its roots become crowded, usually every one to two years, depending on its growth. Spring is generally a good time to repot a healthy rubber plant.