Some tips for caring for gardenia houseplants are to make sure it grows in bright light and high humidity and is well-fed and well-watered. This is challenging, as most homes are filled with air that is hot and dry. Proper sunlight may also be hard to come by.
The gardenia houseplant does best if it has direct sunlight for at least half the day. During the winter, the short and sometimes gloomy days can be supplemented with plant-grow lights. The plant also does better if the room is cool at night. Experts recommend 55 degrees Fahrenheit. During the day, the room temperature should be about 10 degrees warmer.
Since the houseplant gardenia needs high humidity, one way to provide it is to place a group of houseplants on a tray filled with wet pebbles. Turning on a humidifier is another way to regulate the humidity in the room, as is hand misting with a spray bottle, though hand misting is the least effective option.
The homeowner should take care not to overwater or overfeed the plant. Too much water prevents the roots from getting air, and too much fertilizer damages the plant. The homeowner should check the soil now and then, and water if the top inch has dried out. Fertilizer for flowering, acid-loving plants is best. Azalea food is a good choice.