How to Grow Lavandula Dentata Indoors

Fill the bottom of the container with 1 to 2 inches of gravel, broken pottery pieces or Styrofoam packing peanuts. This allows soil to completely drain between waterings. Using a lighter material makes it easier to move the containers around during the year.

Fill the rest of the container with slightly moistened, sterile potting mix and a slow-release fertilizer, following the manufacturer's recommended dosage.

Make a well in the center of the container to accommodate the root ball of the starter plant. The plant's base should sit even with the top of the soil when placed in the prepared hole.

Pack soil gently around the sides and on top of the plant's base, up to the stem, patting soil to remove any large pockets of air.

Water the plant to allow it to settle into the container. After the lavender is established, maintain a regular watering schedule. Soak the soil thoroughly and let it completely drain, removing any water standing in the saucer afterward. According to Arizona State University, allowing the top layer of soil to dry before rewatering helps promote compact, bushy growth. Decrease the amount of water given during the winter months; however, do not let it dry out completely.

Place the container in a location that gets full sun for at least six to eight hours per day. Rotate the container several times a week to ensure that all sides of the plant get adequate light. If you don't have the appropriate amount of natural sunlight, use growing lights to provide additional light.

Apply slow-release fertilizer at least once a month, at watering time, following the recommended dosage amounts. Because of the dense root structure, French lavender quickly leaches nutrients from the soil and requires a bit of help to maintain its beauty.

Prune lavender each year, after the blooming period, to promote branching, fuller growth and better air circulation. The Colorado State University Cooperative Extension recommends cutting lavender down to one-third of its original size, while maintaining the general shape of the plant.