Growing stevia as a sweet herb
*Stevia rebaudiana* is a short-day perennial from the Amambay region of Paraguay and Brazil, grown in temperate North America as a warm-season annual. The leaves contain steviol glycosides -- primarily stevioside and rebaudioside A -- that are 200-300 times sweeter than sucrose by weight, per USDA.
—- title: "Growing stevia as a sweet herb" slug: growing-stevia hub: vegetables category: "Herb guide" description: "How to grow stevia (Stevia rebaudiana) outdoors in temperate zones, from transplant to harvest, including drying and overwintering strategies for zone 8 and warmer." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 9 scientific: "Stevia rebaudiana" zones_min: 9 zones_max: 11 sun: "full sun" —-
Stevia rebaudiana is a short-day perennial from the Amambay region of Paraguay and Brazil, grown in temperate North America as a warm-season annual. The leaves contain steviol glycosides — primarily stevioside and rebaudioside A — that are 200-300 times sweeter than sucrose by weight, per USDA Agricultural Research Service. This makes it one of the most useful herbs a kitchen gardener can grow: a single plant produces enough dried leaf material to sweeten beverages for months.
I don't grow stevia at my Long Island plot. The growing season is barely long enough to make it worthwhile, and the flavor of freshly dried leaf is variable compared to commercially processed extract. This guide is sourced from Extension publications.
About the plant
Per Texas A&M AgriLife Extension, Stevia rebaudiana is a tender perennial in USDA zones 9-11, where it can survive winter outdoors. In zones 7-8, it dies back to the roots in mild winters and may re-sprout, but reliable outdoor perennialization is not assured. In zones 2-6, treat as an annual: start indoors, transplant after last frost, harvest before fall frost.
Plants grow 18-30 inches tall with small, slightly toothed green leaves on branching stems. Left to mature, the plant produces small white flowers in fall (triggered by shortening days) that signal the end of the harvest window.
USDA hardiness zones
Per Texas A&M AgriLife Extension, stevia is reliably perennial in zones 9-11. In zones 7-8, survival depends on site conditions — a south-facing wall, excellent drainage, and a thick mulch over the crown give the best chance of overwintering. In zones 2-6, treat exclusively as a frost-tender annual.
Light requirements
Per Texas A&M AgriLife Extension, stevia requires full sun — 6-8 hours minimum. Under shade or partial shade, plants become leggy, produce fewer leaves, and have lower glycoside content. This is not a plant that tolerates compromised light.
Starting from transplant vs seed
Per Penn State Extension, seed germination rates for stevia are highly variable — often below 50% — because many seeds are infertile. Commercially purchased transplants or vegetative cuttings from known-productive plants are the most reliable route. Per NC State Extension, start transplants indoors 6-8 weeks before the last expected frost date under bright light (14-16 hours of artificial light per day).
Transplant outdoors after the last frost date, when nighttime temperatures remain above 50°F. Space plants 18-24 inches apart.
Watering
Per Texas A&M AgriLife Extension, stevia prefers consistently moist but not waterlogged soil. Water at a rate of 1-1.5 inches per week. Drought stress causes premature flowering and a drop in leaf glycoside content. Mulch with 2 inches of straw to retain moisture and keep roots cool.
Soil requirements
Per NC State Extension, stevia performs best in:
- Loamy, well-drained soil
- pH 6.5-7.5
- Moderate organic matter content
It is intolerant of waterlogged conditions; raised beds or mounded rows are recommended in heavy soils.
Fertilizing
Per Texas A&M AgriLife Extension, incorporate compost (2 inches) and a balanced fertilizer (10-10-10 at the label rate) before planting. Sidedress once mid-season with a nitrogen source (calcium nitrate at 1/4 cup per plant) if plants show pale foliage. Avoid over-fertilizing with nitrogen; it promotes vegetative growth but dilutes glycoside concentration in leaves.
Pinching for bushier plants
Per Penn State Extension, pinch out the growing tips of young transplants once they reach 8 inches tall, and again when lateral branches reach 8 inches. This encourages a bushier growth habit with more harvestable leaf surface. Unpinched plants become leggy with a central stem and sparse leaves.
Harvesting leaves
Per Texas A&M AgriLife Extension, leaves have the highest stevioside concentration just before the plant initiates flowering. Watch for flower bud development (usually as day length drops below 12-13 hours in fall) and harvest before buds fully open.
For a final large harvest at season's end, cut the entire plant to 4-6 inches above the soil. Bundle stems and dry at 70-80°F with good air circulation for 3-4 days. Separate leaves from stems once dry. Dried leaves can be used whole in beverages or ground to a powder.
Per USDA Agricultural Research Service, the sweetness of home-grown dried leaf varies considerably based on drying method, cultivar, and timing. Commercial stevia extract is produced via water extraction and purification; home-dried leaf used directly in beverages will have a slightly green, herbal note in addition to sweetness.
Overwintering in zone 8-9
Per Texas A&M AgriLife Extension, in zones 8-9:
- After first light frost, cut plants back to 3-4 inches
- Apply 4-6 inches of straw mulch over the crown
- Remove mulch when nighttime temperatures stay above 40°F in spring
- Expect new growth to emerge from the crown in late spring
In zone 8, overwintering success is roughly 50% even with protection. Plan to start new plants annually as a backup.
Pests and diseases
Stevia has few serious pest problems when grown in appropriate conditions. Per UC IPM:
Aphids: Common on new growth. Dislodge with water spray; treat severe infestations with insecticidal soap.
Thrips: Fine streaking or silvering on leaves. Per UC IPM, reflective mulches can reduce thrips pressure; spinosad is effective if treatment is needed.
Root rot (Sclerotinia): Occurs in wet, poorly-drained soil. Prevent with good drainage and avoiding overwatering.
Common problems
| Symptom | Likely cause | Fix |
|---|---|---|
| Leggy, sparse leaves | Insufficient light or no pinching | Full sun site; pinch tips early |
| Premature flowering | Short days + heat stress | Harvest leaves immediately; cannot reverse |
| Low sweetness | Harvest after flowering, wrong cultivar, or over-fertilized | Harvest pre-flower; choose named cultivars |
| Plant dies after transplant | Frost exposure or wet soil | Harden off properly; improve drainage |
| Poor germination from seed | High infertility rate | Use vegetative cuttings or commercial transplants |
Frequently asked questions
Is home-grown stevia as sweet as commercial stevia? Per USDA Agricultural Research Service, fresh stevia leaf contains 4-20% stevioside by dry weight, depending on cultivar and growing conditions. Commercial products are refined to purified rebaudioside A. Home-dried leaf is sweeter per gram than sugar but less concentrated than commercial extracts, and has a herbal background note that some people find unpleasant. The sweetness profile is better suited to hot beverages than baked goods.
Can I grow stevia on Long Island (zone 7a)? Yes, as an annual. Start transplants indoors in late March under grow lights. Transplant in late May. Harvest in September before the first fall frost. The season is workable but short — pinching early to maximize leaf production is important. Do not expect perennialization; treat as an annual each year.
Which stevia cultivar has the best flavor? Per NC State Extension, improved cultivars with higher rebaudioside A content (the glycoside with the cleanest, least bitter sweetness) include 'Candy', 'Sweet Lace', and 'Sugar Plum'. The straight species produces acceptable flavor but named cultivars are worth seeking out for culinary use.
Can I take cuttings to overwinter stevia indoors? Per Texas A&M AgriLife Extension, yes. Take 4-inch tip cuttings in late summer before the plant flowers. Root in moist perlite under bright artificial light (14-16 hours). Keep at 65-70°F through winter. Transplant outdoors the following spring. This is the most reliable way to preserve a productive plant.
Recommended gear: Best LED Grow Lights for Seedlings (2026) — our buyer's guide covering picks for every budget, ranked by Extension publication consensus and personal use.
Sources
- Texas A&M AgriLife Extension — Stevia
- NC State Extension — Stevia rebaudiana
- Penn State Extension — Herbs
- USDA Agricultural Research Service — Stevia research
- UC IPM — Aphids and thrips management