If growing your own calorie-free, natural sweetener sounds too good to be true, it’s time to get to know stevia. Native to Paraguay and other tropical areas of the Americas, the stevia plant (Stevia rebaudiana) produces leaves packed with super-sweet compounds that remain stable even after the leaves have been dried. Stevia leaves have been used to sweeten teas and beverages throughout South America for centuries. More recently, diabetics and dieters alike have turned to stevia to reduce their sugar intake because, unlike honey, maple syrup, agave or molasses, this natural sweetener has zero CALORIES and is not metabolized by the body. Stevia is especially well-suited to sweetening drinks, fruits, salad dressings, yogurt and most creamy desserts. Stevia can substitute for some, but not all, of the sugar used when baking, because it does not provide all of the multiple functions that sugar does.
Growing Stevia Plants
Growing stevia is easy in well-drained beds or large containers, and the leaves can be dried for winter use like any other herb. Stevia grows best in warm conditions similar to those preferred by basil. Plants grown in warm climates will grow to 24 inches tall and wide. Where summers are cool, expect stevia plants to grow up to 16 inches. Grow three to five plants for a year’s supply of dried stevia leaves.
Stevia can be started from seed indoors in late winter, but it’s best to grow it from rooted cuttings. Germination of stevia seeds tends to be spotty, so keep seed-sown plants under bright lights until the weather warms in spring. Look for stevia plants in the herbs section at garden centers, or locate mail-order suppliers using our Seed and Plant Finder.
Choose a well-drained site, and set out the plants 2 feet apart after your last frost. Be sure to choose an accessible spot, because you will need to gather stems often. Where summers are extremely hot, stevia benefits from slight afternoon shade. Elsewhere, grow stevia in full sun.
Left unpruned, stevia will grow into a lanky, upright plant that produces tiny white flowers in late summer. To maximize leaf production, you must trim back the plants several times to induce branching, first when plants are about 8 inches tall, and again in early summer. You can use the leaves from the pinched-back stem tips, or root them in moist potting soil to increase your supply of stevia plants.
The Care and Feeding of Stevia
Stevia plants do best in a rich, loamy soil the same kind in which common garden-variety plants thrive. Since the feeder roots tend to be quite near the surface, it is a good idea to add compost for extra nutrients if the soil in your area is sandy.
Besides being sensitive to cold during their developmental stage, the roots can also be adversely affected by excessive levels of moisture. So take care not to overwater them and to make sure the soil in which they are planted drains easily and isn’t soggy or subject to flooding or puddling.
Frequent light watering is recommended during the summer months. Adding a layer of compost or your favorite mulch around each stevia plant will help keep the shallow feeder roots from drying out.
Stevia plants respond well to fertilizers with a lower nitrogen content than the fertilizer’s phosphoric acid or potash content. Most organic fertilizers would work well, since they release nitrogen slowly.