Key Features
- Warm-season annual legume known for fast, upright growth and abundant foliage.
- Produces yellow flowers followed by slender seed pods when allowed to mature.
- Excellent choice for cover cropping, green manure, erosion control, and soil-building programs.
- Thrives in warm conditions and adapts to a range of well-drained soil types.
- Tall, vigorous plants can add substantial organic matter when incorporated into soil.
Growing Benefits
- Helps add valuable plant biomass to garden soil when used as green manure.
- Provides useful ground cover during warm growing periods.
- Supports soil improvement as part of a crop rotation strategy.
- Fast-growing foliage can help suppress competing weeds.
- Suitable for gardens, fields, orchards, and sustainable growing systems.
Seed Specifications
- Common Name: Sunn Hemp, Sun Hemp
- Botanical Name: Crotalaria juncea
- Plant Type: Warm-season annual legume
- Colors: Green foliage with yellow flowers
- Height: About four to eight feet
- Sunlight: Full sun
- Soil: Well-drained soil; adaptable to various soil types
- Water: Moderate watering; drought tolerant once established
- Germination Time: Usually about four to seven days under suitable conditions
- Sowing Depth: About one-half to one inch deep
- Spacing: About four to twelve inches apart for cover-crop planting
- Growing Zones: Best suited to warm climates; generally USDA Zones eight through eleven
- Flowering/Maturity: Typically flowers within several weeks to a few months, depending on growing conditions and variety
- Uses: Cover crop, green manure, soil-building, erosion control, weed suppression, and biomass production
Growing Tips
- Sow only after the soil has warmed, as sunn hemp performs best in warm conditions.
- Choose a sunny location with good drainage for vigorous growth.
- Keep newly planted seeds consistently moist until seedlings become established.
- Mow or terminate the crop before mature seed production when using it as green manure.
Seed Storage
Keep sunn hemp seeds in a cool, dry, dark location away from moisture and heat. Store them in an airtight container or sealed seed packet and protect them from humidity, pests, and direct sunlight.
Unique Facts About Seeds
- Sunn hemp is a legume belonging to the Crotalaria genus and is widely grown as a warm-season cover crop.
- Its rapid biomass production makes it useful for green manure and soil-management systems.
- The plant develops distinctive yellow pea-like flowers on tall, upright stems.
- Sunn hemp is different from industrial hemp and is not cultivated as a fiber or cannabinoid crop in the same way.