Roselle Seeds - Jamaican Sorrel - Hibiscus sabdariffa

5, 6, 7, 8, 9, 10, 11

USDA Zones 5-11 - Roselle is a tropical plant grown as a warm-season annual in most of the US. It can grow as a tender perennial in the truly frost-free climates of Zones 10-11. A long, hot growing season is essential for a successful harvest.

Best performance in Zones 8-11 where long, hot, and humid summers allow the plant to grow into a large, vigorous shrub before it begins to flower and produce its harvest in the fall.

Northern Zones (5-7) - Starting seeds indoors 6-8 weeks before the last frost date is essential. The goal is to give the plant the longest possible growing season so it can reach a large size before the shortening days of fall trigger it to flower.

Hot Climate Zones (8-11) - Direct sow seeds outdoors once the soil is very warm and the weather is consistently hot. In places like Texas, planting in late spring (May to early June) gives the plant the whole summer to grow into a large, productive shrub for a bountiful fall harvest.

Soil Temperature - Roselle demands warm soil. The soil must be at least 75F for germination, with an optimal temperature of 80-85F. Planting in cool soil will cause the seeds to rot.

Growing Season - Requires a long season of 120+ frost-free days. Roselle is photoperiodic, meaning it sets flowers based on day length. It will grow all summer and then begin to produce its harvest of calyces in the fall (typically October/November) as the days shorten.

Learn more about USDA Hardiness Zones here

Planting Roselle (Hibiscus sabdariffa) Seeds
Growing Roselle is a rewarding experience, bringing a taste of the tropics to your garden. Success depends on giving it the heat, sun, and time it needs to thrive.

Please Note: As of mid-August, it is too late to plant Roselle from seed and expect a harvest this year. These instructions are for your garden plan for next spring.

When to Plant
Roselle needs heat and a long runway to grow.

Starting Indoors (Recommended for Zones 8 and below): Start seeds indoors in pots 6-8 weeks before your last frost date. This head start is crucial for getting a large, productive plant.

Direct Sowing (Zones 9+): Wait until the weather is thoroughly hot and settled. Sow seeds directly in the garden when soil temperatures are reliably above 75F, typically in May or early June.

Where to Plant
Sunlight: Choose the sunniest, hottest location in your garden. Roselle requires at least 8 hours of direct, intense sunlight per day.

Space: This plant gets big! Give it plenty of room to grow into a large shrub. Space plants at least 3-4 feet apart in rows that are 4-5 feet apart.

Soil: Roselle prefers well-drained, sandy loam soil. While it can tolerate average soil, enriching your soil with compost will improve your harvest. A soil pH between 6.0 and 7.0 is ideal.

How to Plant
Prepare Seeds (Recommended): The seeds have a hard coat. To improve germination, gently nick the seed coat with a nail file (scarification) and then soak the seeds in warm water overnight.

Sowing: Plant the prepared seeds 1/2 inch deep.

Watering: Water the area well after planting and keep it moist until germination, which can take 1-2 weeks in very warm soil.

Thinning: If you plant multiple seeds in one spot, thin to the single strongest seedling once they are a few inches tall.

Care & Maintenance
Watering: Water regularly after planting until the plants are well-established. Mature plants are quite drought-tolerant but will be more productive with consistent moisture, about 1 inch of water per week.

Pinching: When the young plants are about 12-18 inches tall, you can pinch off the very top growing tip. This will encourage the plant to branch out, creating a bushier form with more flowers and calyces.

Fertilizing: Roselle is not a heavy feeder. Avoid high-nitrogen fertilizers, which will produce lots of leaves but few flowers. Amending the soil with compost at planting time is often enough. If you do fertilize, use a formula that is higher in phosphorus to promote blooming.

How to Harvest
The prize of the Roselle plant is the fleshy, bright red calyx that surrounds the seed pod.

Timing: The harvest begins in the fall, typically in October and November, about 2-3 weeks after the flowers bloom. Each flower lasts only a day, but the calyx will grow and plump up after the petal drops.

Harvesting the Calyx: Harvest when the calyces are plump, crisp, and deep red. Simply snap them off the plant by hand or use pruners. You can harvest continuously for several weeks.

Processing: To use the calyx, you must remove the hard, green seed pod from inside. Use a small knife, an apple corer, or a specialty coring tool to push the pod out from the bottom. The hollowed-out red calyces can then be used fresh or dried for later use in teas and drinks.