How to grow Stevia

Where to plant

Grow stevia in full sun or light shade in moist, well-drained, slightly acid, sandy loam rich in organic matter. It likes moderate temperatures and humidity but rots in soggy soil. Mulch helps hold moisture and keep weeds down.

Stevia is a tender perennial, hardy only in about zones 10 and 11. Elsewhere, grow it as an annual or keep it in a pot and bring it indoors before the first frost.

• South and Central Florida and Hawaii: can be grown as a perennial in a well-drained spot. Plant in late winter to spring or late summer.
• North Florida, the Gulf South, Texas and the Desert Southwest: plant in spring and again in late summer, and protect or pot up plants before frost. In the desert, give it afternoon shade.
• California: plant in spring; it may overwinter in frost-free coastal gardens.
• Mid-South, Mid-Atlantic, Southern Plains and all colder regions: plant outdoors in May or June after the last frost and treat it as an annual, or overwinter it indoors in a pot.

How to plant

1. Start with a nursery plant or a rooted cutting. Seed germinates very poorly and seedlings vary in sweetness.
2. Plant after the last frost, 12 to 18 inches apart, in well-drained soil with compost.
3. Water in and mulch.
4. Pinch out the tips when plants are about 8 inches tall to make them bushy; the stems are weak and flop if left unpinched.

Watering and feeding

Keep the soil evenly moist but never waterlogged. Stevia does not tolerate drought well, and wet, heavy soil causes root rot.

Feed lightly with compost or a balanced fertilizer. Heavy nitrogen gives lush growth with less sweetness.

Pruning and care through the year

• Pinch the tips regularly through summer to keep plants compact.
• Remove flower buds as they form if you want to keep picking sweet leaves; leaves lose sweetness once the plant flowers.
• In cold areas, pot up a plant or take cuttings in late summer and keep them on a sunny windowsill over winter.

Harvesting

Pick leaves as needed through summer. The sweetness is strongest in fall, just as the plant begins to flower, so that is the time for the main harvest. Cut whole stems, strip the leaves and dry them in a warm, airy place out of the sun, which concentrates the sweetness. Store dried leaves in a sealed jar.

Growing in pots

Stevia grows well in a pot at least 8 inches wide with a free-draining mix, outdoors in summer and on a bright windowsill in winter. Water when the top of the mix starts to dry.

Using it

Add a fresh leaf to tea or lemonade, or crumble or grind dried leaves to sweeten drinks and desserts. A little goes a long way, and the leaves have a slight licorice aftertaste. Home-dried leaves do not behave like sugar in baking.

Propagation and saving seed

Take tip cuttings 3 to 4 inches long in summer, remove the lower leaves, dip in rooting hormone and root them in moist potting mix under a clear plastic dome or bag. Cuttings keep the sweetness of the parent plant.