Black Sesame Harvesting and Post-Harvest Handling

When should black sesame be harvested?

Direct answer: harvest when a representative majority of the crop shows the maturity signs defined for the chosen variety, before avoidable shattering, pod opening or weather damage. Do not judge from one border plant. TNAU advises using several maturity signs together: lower-leaf shedding, yellowing of upper leaves and stems, capsule colour change and full varietal seed colour. Harvest before widespread capsule opening causes shattering loss.

What signs show maturity?

Sample the crop instead of relying on one border plant

• Lower leaves begin to shed.
• Upper leaves and stems lose green colour and turn yellow.
• Capsules change colour progressively.
• Seeds sampled from representative capsules show the full dark colour of the variety.
• The crop is mature enough to cure after cutting but has not begun widespread shattering.

Open and inspect samples from several positions. Compare seed colour and hardness with the varietal description. Record the observation and expected weather before deciding whether to pick mature units, cut plants or wait.

Why can harvest timing reduce losses?

Sesame capsules can open naturally as they mature. Wind, handling and waiting too long can spill seed before it reaches the threshing sheet. Dark seed also shows admixture with pale sesame clearly, so cleaning equipment and keeping lots separate is especially important.

Harvesting very early leaves more immature, high-moisture seed. Harvesting too late can increase field loss, weathering, insects or quality variation. The best point balances maturity with the crop's shattering habit and the farm's ability to dry promptly.

How should harvested material be handled?

1. Use clean cutting, picking and collection equipment.
2. Keep plants and pods off damp or bare soil.
3. Separate visibly diseased or heavily infested material.
4. Move harvested material to the drying area without compacting a wet mass.
5. Maintain lot identity by variety, field and harvest date.

How should the crop be dried?

Dry promptly in thin layers, manageable bundles or another locally recommended system with good air movement. Protect the crop from unexpected rain and night moisture. Turn or rearrange it so the centre and edges dry evenly. Avoid using appearance alone to decide that the seed is safe for storage.

Measure seed moisture where possible. The correct target depends on whether the lot is food grain or planting seed, the storage duration, the container and the applicable buyer or certification standard. Do not seal warm seed; temperature differences can create condensation inside a bag or bin.

How are threshing and cleaning done?

Thresh on a clean sheet or floor and adjust machinery to reduce cracked or split seed. Winnow or screen out stems, chaff, soil, stones, weed seeds and light damaged grain. Clean equipment between lots, especially where black and white sesame or different seed classes must remain separate.

How should the clean lot be stored?

• Use clean, dry, food-suitable or seed-suitable containers as applicable.
• Label crop, variety or market class, lot, field, harvest date and measured moisture.
• Keep bags on pallets and away from walls, leaks and direct sun.
• Inspect for insects, heating, odour, condensation, caking or moisture migration.
• Use first-in, first-out stock control where quality requirements permit.
• Never apply an unapproved chemical directly to food grain.

What should a storage inspection record?

Use a simple log with lot identity, bag count or bin, inspection date, measured moisture where available, temperature or heating observations, insects, odour, roof or wall dampness and action taken. Inspect more closely after humid weather, building leaks or movement of old stock.

Sample from more than the top bag. Warm pockets and moisture migration can occur inside a stack. If a lot changes, isolate it and obtain appropriate food, seed or storage advice before blending, treating or selling it.

What quality defects should buyers and farmers watch?

Signal	Possible concern	Response
Musty or sour odour	Moisture, heating or microbial deterioration	Isolate and assess the lot; do not mix it with sound grain.
Condensation or warm pockets	Seed stored too warm or wet, or moisture migration	Measure condition and obtain storage advice promptly.
Exit holes, webbing or live insects	Storage-pest activity	Segregate, identify and use an approved management protocol.
Many immature or discoloured seeds	Early harvest, uneven maturity or field/weather damage	Grade separately and confirm buyer specifications.
Stones, soil or other crop seed	Poor harvest-floor hygiene or cleaning	Reclean and trace the contamination point.