Growing Stevia rebaudiana indoors offers a continuous supply of this natural, calorie-free sweetener, especially for those living in cooler climates where the plant cannot survive outdoors year-round. Stevia, a perennial herb native to South America, contains compounds in its leaves that are significantly sweeter than sugar. By providing an environment that mimics its native subtropical home, you can easily cultivate a healthy and productive stevia plant on a sunny windowsill or under lights. This indoor cultivation method allows growers to extend the natural growing season and harvest fresh leaves whenever they are needed.
Creating the Right Indoor Habitat
The most important factor for successfully growing stevia indoors is providing sufficient light, as the plant naturally thrives in full sun. Stevia requires a minimum of 12 hours of light daily to produce the sweetest leaves and prevent the plant from becoming spindly or “leggy.” If a south-facing window cannot provide this duration of direct, bright light, supplemental artificial lighting is necessary.
Full-spectrum LED or fluorescent grow lights are effective alternatives for indoor cultivation. Position the light source approximately 6 to 12 inches above the top of the plant canopy to ensure high light intensity. Maintaining a warm environment is also important; ideal daytime temperatures range between 70 and 75°F, and nighttime temperatures should not drop below 60°F. Maintaining good air circulation around the plant with a small fan helps to prevent fungal issues that can arise in stagnant indoor air.
Soil, Potting, and Drainage Needs
Selecting the proper container and growing medium is essential for managing moisture and supporting the plant’s root system. Choose a pot that is wider than it is deep, with a diameter of at least 12 inches for a mature plant, and ensure the container has multiple, adequately sized drainage holes. Stevia is highly susceptible to root rot, so excellent drainage is mandatory.
A high-quality, lightweight potting mix provides the best foundation for indoor stevia. The mix should be well-draining, such as a standard potting soil amended with perlite or coarse sand to increase aeration and prevent compaction. Stevia prefers a slightly acidic to neutral pH, ideally between 6.7 and 7.2, and a well-balanced mix will help maintain this range.
Routine Care and Upkeep
Consistent watering is a delicate balance, as stevia dislikes both overly dry and soggy conditions. Allow the top inch of the potting mix to dry out completely between waterings before thoroughly saturating the soil until water drains from the bottom. Overwatering is the most common cause of failure for indoor stevia, so monitor soil moisture carefully before each watering.
Stevia is a light feeder and does not require heavy fertilization. During the active growing season, from spring to fall, apply a diluted, balanced liquid fertilizer once a month. Pruning is a necessary maintenance task for indoor stevia to promote a dense, bushy shape and maximize leaf production. Pinch back the growing tips of the stems when the plant reaches about 8 inches tall, making the cut just above a leaf node to encourage new lateral branches.
Good air circulation and proper humidity management help deter common houseplant pests like spider mites and aphids. Inspect the undersides of the leaves regularly and treat any infestations immediately with non-toxic methods, such as an insecticidal soap spray.
Harvesting and Storage Tips
The best time to harvest stevia leaves for maximum sweetness is just before the plant begins to flower, as the plant directs energy away from leaf sweetness once flowering starts. Cooler temperatures in the fall can also intensify the leaf sweetness. It is best to harvest by cutting entire stems, rather than plucking individual leaves, ensuring you never remove more than one-third of the plant at one time to allow for continued growth.
To preserve the harvest, dry the cut stems by hanging them upside down in a cool, dark, and well-ventilated area until the leaves are completely brittle. Alternatively, a food dehydrator set to a low temperature can speed up the process. Once dried, strip the leaves from the stems and store them in an airtight container, away from light and heat, to maintain their potency for up to a year. The dried leaves can be crumbled or ground into a powder or steeped in warm water to create a liquid extract.