The next time you want to sweeten your coffee or tea, don't reach for the sugar bowl or packets of artificial sweetener. Instead, step outdoors to your sunny herb garden and pick a leaf or two of stevia, the easy-to-grow herb that has garnered national attention since the Food and Drug Administration recently approved its use as a food additive.
U.S. health food stores have sold stevia-based products such as SweetLeaf and Truvia as dietary supplements for some time. But now with the FDA's go-ahead, soft drink giants Coca-Cola Co. and PepsiCo will introduce zero-calorie beverages using extracts of Stevia rebaudiana to the mainstream market. The natural alternative should appeal to health-conscious consumers wary of artificial sweeteners.
While it may be new to the U.S. market, stevia has been used worldwide for centuries. A South American native, the herb produces green leaves that contain stevioside, which is much sweeter than sugar but contains no calories and doesn't affect blood sugar levels. Commercially, its leaves are steeped in water and purified with ethanol to create a crystalline powder that's purported to be 200 times sweeter than sugar. In the home garden, you can simply pick a fresh leaf or two to satisfy a sweet tooth directly or add to foods and beverages. You can also harvest and dry leaves, crush them and store for later use or steep leaves to make a liquid. Stevia can have a licorice flavor if you use the fresh leaves, but commercial products typically don't have this licorice flavor.
Experts recommend using starter plants rather than seed, which are difficult to germinate. Most garden centers sell stevia, including the big box retailers. There are numerous mail-order suppliers as well (see box).
A member of the chrysanthemum family, stevia should be planted in rich, organic soil in full sun (at least six hours of direct sun each day). Although it needs consistently moist soil, make sure the pot or container provides good drainage because the plant won't tolerate "wet feet." Its roots are shallow, so topping the soil with compost or mulch will help retain some moisture, especially during dry spells. Like many herbs, stevia prefers feedings with a low-nitrogen content or slow-release fertilizer, preferably an organic one.
Retired horticulturist and herb expert Allen Cordell of Largo recommends regularly pinching off the plant's blooms to promote bushy growth and more leaves. At maturity, stevia plants will reach about 30 inches high and 18 to 24 inches wide, but they aren't perennial. Like other Florida-grown herbs, such as parsley, stevia plants should be replaced every 18 to 24 months, Cordell says.
You can keep a constant supply growing by introducing new plants into the herb garden at intervals, such as every six months to a year. Florida summers always pose a challenge for herbs, Cordell notes. Move containers into more filtered sun during summer months and water each day, especially if there has been no rain.
If you want to harvest a large quantity of leaves, experts recommend using both leaves and the tips of stems, which contain as much stevioside as leaves. For dried leaves, place the fresh cuttings on a screen or net in full sun to dry in a protected spot. Then crush the leaves by hand or use a coffee grinder. Store the dried leaves in an air-tight container. To create a liquid, add 1 cup of warm water to ¼ cup of fresh, finely crushed leaves (not dried). Let the liquid mixture set for 24 hours, then refrigerate.
While those with a sweet tooth will enjoy growing stevia, not everyone is attracted to its sweetness. It seems that aphids, grasshoppers and other pests are repelled by the plant, which is good news for the home gardener.
Yvonne Swanson is a writer and Pinellas County master gardener. Contact her at firstname.lastname@example.org.