Keep terrariums in the bright spot in your house. They love an indirect sunny window sill, and also thrive under bright artificial light, making them ideal accents for your desk at work or school. Outdoors most terrariums like indirect light as well. They don't need to be watered very frequently. Once every couple of weeks -- or less -- may suffice, depending on the variety, the size of the container, soil dryness and the amount of light and temperature it gets. You typically don't need to worry about pruning them. Just remove the leaves that have fallen to avoid rotting. You can fertilize if you want for faster growth with any general-purpose fertilizer. Note: While they're beautiful and easy-care plants, terrarium plants are not intended for human or animal consumption.