Gardening Articles: Edibles :: Herbs
Sweet Stevia (page 2 of 3)
by Kathy Bond Borie
Stevia likes heat and can be grown as a perennial in frost-free areas. Elsewhere, the best approach is to treat it as an annual herb such as basil. For best results, plant stevia in the garden for the summer, harvest the fresh leaves before flowering, and dry them for later use.
Transplants can be ordered from a mail-order nursery in the spring and planted in the ground when the soil temperature reaches about 65°F. A sandy loam with a slightly acid to neutral pH and good drainage is important. If your soil is heavy clay or otherwise slow-draining, plant in a raised bed or container filled with lightweight soil mix. (Because the stems tend to be brittle, group plants close together so they can help each other withstand winds and rain.)
Stevia has a temperamental nature that is often reflected in slow growth when the plants are first set out. After the first month, they pick up speed. They're not picky about fertilizer; any general liquid fertilizer, such as a 20-20-20, applied once a month during the summer will do. Pruning and pinching encourage bushy plants. Always pinch off flowers in order to produce the sweetest leaves.
When fall arrives, it's time to harvest the leaves. Pull up the plants in the early morning and remove the leaves, then dry them in the sun for about 24 hours. When crispy dry, the leaves can be stored in a plastic bag or airtight jar. They can be ground easily in a mortar and pestle or in an electric spice or coffee grinder.
One way to extend the harvest of sweet leaves is to overwinter garden plants indoors, or order stevia plants in the fall and grow them inside until spring. Pot them in a lightweight soil mix and keep them in a 70°F room.
If you like to experiment, you can make your own cuttings from outdoor plants during the summer. Three-inch tip cuttings dipped in rooting hormone will root in sand if misted frequently. Stevia cuttings can also be rooted in water. Grow lights are essential to keeping stevia plants happy indoors. Even under ideal conditions, it's not uncommon for plants to die suddenly or to lose leaves and appear dead, but as long as the roots are alive, they may regrow.