Private: Stevia(Stevia rebaudiana)
Light requirements: Full sun.
Planting: Space 18 inches apart.
Soil requirements: Plants grow best in loose, loamy, well-drained soil. Stevia also adapts well to containers. Good drainage is vital. Don’t enrich soil heavily with compost, as too much nitrogen dilutes leaf sweetness.
Water requirements: Keep soil moist after planting until plants are well-rooted. Once established, water weekly if rainfall doesn’t occur (twice weekly in warmest zones). In containers, irrigate whenever the top inch of soil is dry. Mulch soil to prevent surface feeder roots from drying out.
Frost-fighting plan: Stevia is perennial in zones 9 to 11 and overwinters in zone 8 with protection. Established plants can survive a few light frosts (above 32º F). Use a frost blanket to protect newly planted seedlings from late spring frosts or prolong the fall growing season. Shift potted stevia indoors in coldest zones to grow through winter.
Common issues: Good drainage is vital for growing in every zone—and especially for successful overwintering in zone 8. Stevia is susceptible to root rot in poorly drained soils or when overwatering occurs. Clip flower stalks as soon as they appear; once plants start blooming, leaf size diminishes immensely and flavor becomes slightly bitter. Insects seem to avoid stevia. Some gardeners plant it to help prevent other plants from insect infestation.
Growing tip: Clip stem tips often when plants are young to encourage branching and bushiness. This yields more leaves.
Harvesting: Pick leaves at any point in the growing season, although it’s worth waiting for leaves to enlarge. Cut an entire stem if desired, or just pinch a leaf. Clip entire stems (to dry leaves) at the end of the growing season in zones where frost will kill plants.
Storage: Keep stems in a water-filled vase and harvest leaves freely. Stems should last up to a week, but flavors tend to shift as stems start to fade. Or wrap fresh stems in a barely damp paper towel and tuck into a loosely closed plastic bag. Store in a warmer part of the refrigerator (like the door). Use leaves within a week. For longer storage (and stronger flavor), dry leaves.
For more information, visit the Stevia page in our How to Grow section.