How to Grow Stevia UK | Regional Planting Calendar

Regional Planting Calendar

Quick Facts

Factor	Value
Soil pH	5.5 - 7
Sunlight	2-6 hours direct sun
Soil texture	Loamy or sandy (RHS; NC State Extension)
Drainage	Moist but well-drained -- overwatering causes root rot (NC State Extension)
Lifecycle	Tender perennial usually grown as a half-hardy annual outside USDA zones 10-11 (RHS; NC State Extension)
Edible parts	leaves

At a Glance

Soil & Growing Conditions

Water: Moist but well-drained; keep evenly moist without waterlogging (RHS; NC State Extension)

Soil pH range

5.5 7

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage	BBCH	Notes
Sowing and germination	0	Propagate by seed, or by stem cuttings (NC State Extension). RHS recommends sowing under cover and planting outside only after all risk of frost has passed, since stevia is frost-tender.
Vegetative growth	3	Grow on in full sun to partial shade in moist, well-drained, slightly acidic to neutral soil. Fertilize every 4-6 weeks during the growing season; avoid overwatering, which causes root rot (NC State Extension).
Flowering	6	Blooms July to August with small white tubular flowers in loose clusters. Pinching out flower buds is recommended to keep leaf flavour at its sweetest (NC State Extension).
Harvest	8	Leaves are ready roughly 90 days after planting, and are sweetest picked just as flowering begins. Grown as an annual in most climates, stevia is moved indoors or discarded before the first autumn frost unless in USDA zones 10-11, where it survives as a perennial (NC State Extension).

Harvest & Storage

When to pick: Leaves are ready to harvest around 90 days after planting, and are sweetest if picked just as the plant begins to flower in July or August; pinching out flower buds helps keep leaf flavour at its best (NC State Extension). Fresh leaves can be used for tea, but dried leaves are usually sweeter than fresh ones (NC State Extension).

Diseases

Pests

Thrips

low

Thysanoptera

RHS names thrips directly on its Stevia rebaudiana plant page.

Aphids

low

Aphididae (various spp.)

NC State Extension names aphids as an occasional pest issue for stevia.

Glasshouse red spider mite (two-spotted spider mite)

low

Tetranychus urticae

NC State Extension names spider mites as an occasional pest issue for stevia.

Stevia Photo Gallery

Stevia leaves close-up

The serrated, elliptic leaves of Stevia rebaudiana, the source of its natural sweetener compounds.

Stevia specimen, Dresden Botanic Garden

A cultivated Stevia rebaudiana specimen showing the plant's upright, branching growth habit.

Flowering Stevia in a container

A potted Stevia plant in flower, showing the small white tubular blooms that appear from midsummer.

Dried Stevia leaves

Dried Stevia leaves, the harvested and processed form used as a natural sweetener.

Mature Stevia plant

A full, bushy Stevia rebaudiana plant showing its typical branching structure at maturity.

Stevia grown in rows

Stevia plants grown in a garden row, showing typical field spacing.

Stevia specimen, US Botanic Garden

A labelled Stevia rebaudiana specimen on public display, confirming identification.

Young Stevia plants in nursery pots

Young Stevia plants ready for transplanting, sold as nursery starts.

Stevia leaf detail

A close view of Stevia rebaudiana's toothed leaf margins and paired leaf arrangement.

References

1. NC State Extension Gardener Plant Toolbox - Stevia rebaudiana (Candy Leaf, Stevia, Sugar Leaf, Sweet Herb of Paraguay, Sweet Honey Leaf, Sweet Leaf)

   USDA hardiness zones 10a-11b. Full sun (6+ hrs) or partial shade (2-6 hrs). Soil pH acidic (<6.0) to neutral (6.0-8.0), loamy or sandy, well-drained. Spacing 12in-3ft. Height/spread 1-2ft. Propagate by stem cuttings or seed. Leaves harvested approx 90 days after planting; best harvested just as it begins to flower; prune flower buds to improve leaf flavour. Keep soil moist -- overwatering causes root rot. Fertilize every 4-6 weeks during growing season. Blooms July-August, small white tubular flowers in clusters. Pest issues: aphids and spider mites. No known serious disease issues (see separate NC State Septoria leaf spot publication, which documents a real disease not mentioned on this general toolbox page). Native to Brazil and Paraguay. In North Carolina grown as an annual, moved indoors before first frost if kept as a perennial.

2. NC State Extension Publications - Septoria Leaf Spot of Stevia

   Caused by the fungus Septoria steviae -- stevia is the only known host. Symptoms begin as small necrotic lesions at the base of the plant that move upward in the canopy under favourable conditions; lesions coalesce causing leaf necrosis and eventual defoliation. Pycnidia form within lesions, releasing conidia spread by rain splash. Disease spreads most rapidly in periods of high rainfall with cool night temperatures (typically September-October in North Carolina). When stevia is grown as a perennial, inoculum overwinters in plant debris and re-infects new stems the following season.

3. Royal Horticultural Society - Stevia rebaudiana (candyleaf)

   Half-hardy tender perennial often grown as an annual. Propagate by seed; plant outside after all risk of frost has passed. Soil: loam or sand, acid/alkaline/neutral, moist but well-drained. Sun: full sun or partial shade, warm sunny position. Hardiness H3 (-5 to 1C min, coastal/mild UK only). Height/spread 0.5-1m. Leaves harvested for use as a natural sweetener; time to maturity 1-2 years. May be susceptible to thrips and a virus disease. Family Asteraceae. Not native to GB/Ireland.

3 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.