Propagation and planting
Sesame is propagated by seed. Sesame seeds are very small, 1000 seeds weighing 2–4 g. Sesame seed can be stored for up to 2 years with little loss of viability provided it is dried to below 8% moisture content and kept in airtight containers. Seed intended for sowing should be cleaned thoroughly to remove debris and poorly filled seeds, and treated with an insecticide. Thorough seedbed preparation is desirable; land preparation as for small grains is usually adequate. Level land is important to ensure an even depth of planting but land may be ridged for better drainage in areas where high-intensity storms are common. Immediately before planting, the land should be harrowed to kill weeds since weed control while sesame plants are small is difficult. Depth of planting is usually 2–5 cm, but can be 10 cm in loose soil. Soil should not be compacted after sowing. Even depth of planting ensures even crop emergence and growth, which facilitates subsequent tillage operations and harvesting.
As sesame is mostly a smallholder crop, sowing is usually done by hand. The seeds are often mixed with dry sand or earth to increase the volume and ensure an even seed distribution. A common seed/sand ratio is 1/3. Seed rates of 2–10 kg per ha are used in pure stands. In intercropping, the seed rate depends on the component crops in the mixture and farmer’s objectives. Plant population is greatly affected by the degree of seedbed preparation and by the weather. Branching cultivars of sesame are very adaptive to spacing and yield well at densities ranging from 30,000–35,000 plants/ha. In Tanzania the highest yields in pure stands are obtained with plant populations of 170,000–200,000 plants/ha. When seeds are drilled in rows, a spacing of 35–50 cm between rows is recommended.