In the Garden
Stevia is a pretty, green plant that looks a little like some of the flowering salvias.
Stevia bears small white flowers in the fall. At this point the plant stretches out and offers fewer good leaves for harvest. Trim off the blooms to keep the plant producing leaves as long as possible.
Although stevia (Stevia rebaudiana) looks like an average green plant, it is an exciting choice for the herb garden because of the natural, calorie-free sweetness found in its leaves. Appreciated by diabetics and dieters, stevia is an annual plant that loves the warm sun and dies back in a freeze. However, in Zone 8 and warmer, it is perennial. Gardeners in frost-free areas can grow it year-round, allowing it to grow into a small shrub. However, vigor declines after the second year, so if you want to harvest the maximum amount of foliage (see below), it pays to replant.
If you lack a piece of ground and garden in containers, give your stevia plant at least a 12-inch pot with a quality potting mix. Place it in full sun, and water whenever the potting soil feels dry in the top inch.
Planting and Care
Plant your stevia so that it has about 18 inches of bed to call its own. In the loose, loamy, well-drained soil that the plant prefers, it will grow 1 to 3 feet in height, depending on the length of your growing season. Wait until after all danger of frost is passed before planting. Feed with compost or Bonnie's Herb and Vegetable Plant Food as directed on the label. Mulch to prevent the plant from drying out on hot summer days. Container-grown plants will benefit from the same fertilizer and mulch.
Troubleshooting
Stevia doesn’t like soggy soil, so make sure that it has good drainage or the roots could rot. A sure sign is wilting that won’t recover after watering. Few insects bother it.
Harvesting and Storage
Leaves are sweetest in the cool temperatures of autumn. They also taste best prior to blooming.
To preserve summer’s plenty and to make stevia convenient to use, dry it. Cut whole stems and then strip the leaves and tender stem tips. Place these on loosely woven fabric or non-metal screening outdoors on a dry, sunny day. One day should be long enough; be sure to bring them in before the dew dampens them again. You can also use a food dehydrator if you have one. Once the leaves are crisp, crush them by hand or powder them with a food processor. Store in an airtight container. Remember, the powdered leaves will not dissolve, but they will sweeten your foods.
Fresh Uses
Use the fresh leaves during the growing season to sweeten tea. The sweetness in the leaves is approximately one-fourth as concentrated as the white, powdered stevia that you buy.
When sweetening with powdered leaves, use about 1/8 teaspoon of dried stevia to equal the sweetness of 1 teaspoon of sugar. Remember, while stevia will withstand the heat of cooking, it will not caramelize like sugar or feed yeast for breads.