Caring for stevia is almost the same in every climate except for overwintering. The leaves can be harvested at any time and eaten fresh or dried and stored. Here is a short checklist for optimal stevia plant care:
- Use Transplants
- Keep it warm
- Well watered
- Regular Prunings
- Overwinter Care
Starts not Seeds
Planting stevia from seed will likely be disappointing. It doesn’t have good germination rates, usually around 10% for experienced gardeners. This is why most people get their plants in the form of starts or cuttings. Because of its recent popularity, stevia can be found in garden supply stores in the spring.
In warm climates, it’s a perennial. In areas where there is frost, it can be grown as an annual. Because it’s a native of the tropics, stevia does not handle the cold well. Make sure the low temperatures in your area are well above 50°F (10°C) before transplanting your starts outside.
Add compost to the soil both to fertilize the new plants and help with additional drainage. Stevia plants need nitrogen-rich soil and constant moisture without being waterlogged. Once your plants are in the ground, mulch them heavily to lock in moisture and add additional nutrients.
Check the soil to make sure there is moisture present. If it feels dry then water more. During summer without rain, you may water two or three times a week. Less watering is necessary with a good layer of mulch. A soaker hose or drip irrigation is recommended, keeping the foliage dry will discourage disease and fungus.
Because the goal with stevia is to produce leaves, pruning will encourage more of them. If left unpruned the plant tends to lengthen stretch out. Do your first pruning when the plant is around 8 inches tall.
Pinch the tips of to lower nodes. The plant will branch and you now have a new stevia start to put into a glass of water for rooting. Or, you can use your trimmings for eating. Prune again in early summer or when you notice it starting to lengthen out.
In USDA planting zones 8 or above, stevia can survive as a perennial. It will die back every year and should be heavily mulched through the cold season for protection. If you live in colder climates, you’ll need to bring your plants indoors. Most people choose two healthy parents to start their plants from next year.
Dig up these plants and prune them down to around 6 inches. Place them in a pot (prune root if necessary) and keep them in a sunny windowsill or heated greenhouse. Come next spring, they will bounce back and you can take additional cuttings.