Growing an indoor gardenia requires careful nurturing. Special attention must be paid to temperature and humidity levels, adequate light, and proper watering, as well as feeding. Gardenias require medium to high humidity, plenty of direct light, and balanced water and fertilizer made especially for acidic soil and blooming plants. In addition, the type of soil in which the plant is housed should be acidic, so care should be taken to ensure that it begins and remains in this state. Lightly pruning your indoor gardenia can also encourage blooming and keep it healthy.
You should place your indoor gardenia in an area where night temperature remains about 60° Fahrenheit (about 16° Celsius) at night. Day temperature should range between 70° and 75° Fahrenheit (21° to 24° Celsius). Indoor gardenias need high humidity, so if you live in a dry climate, a humidifier may be necessary. You can also group several plants together to raise the moisture level. Trays of wet pebbles underneath the grouped gardenias can also maintain humidity.
This fragile plant should be placed near a bright window. Gardenias thrive when they receive direct sun for at least six hours a day. Growing during winter months may require moving your indoor gardenia to an area with southern exposure or using grow lights in addition to natural rays. High temperatures and low light typically cause the flower buds to drop.
Watering your indoor gardenia regularly is essential, keeping the soil evenly moist, but not dry, to the touch. Over-watering can lead to root rot and deprive them of air. When the top inch of the soil is dry, a watering session is required. Keep the gardenia in a planter with adequate drainage and an overflow tray at the bottom. If your plant lives in an unglazed clay or ceramic pot, it will lose moisture more quickly and need more frequent watering.
Your indoor gardenia should be planted in soil with relatively high acid levels, with a pH level between 5 and 6. Choose a gardening soil with this level or especially formulated for acidic plants. Add a small amount of compost to the soil, if desired, or purchase a mix with compost or fertilizer already added. Caution should be taken with any additional fertilizer, however, to avoid burning the plant.
Gardenias need a moderate amount of plant food and specific fertilizer as well as light pruning. Choose a fertilizer formulated for acidic soil and blooming plants, and apply per the manufacturer instructions on the package. Fertilizer may come in a granule form, sticks, or as an addition to water to make a "tea." Use miniature pruning shears to cut off any dead stems or old, woody growth. Dead-heading the flowers by removing spent blossoms is also beneficial.