Seed should be harvested before pods have dried for easy collection and to avoid insect attack. Seed is easily extracted by hand. Freshly extracted seed should immediately be dusted with an insecticide. Seed will remain viable for 3-4 years if kept in opaque, airtight containers. Fresh seed requires no pretreatment if sown immediately after harvest.
Seed collected in previous seasons, however, requires pretreatment to break seed dormancy.
Soaking seed in water for 12-24 hours gives good results and is simple to apply. Seeds can also be nicked. Strict protection from fire and livestock grazing, and efficient control of weed competition during at least the first two years is important to seedling survival. Minimum spacing for block planting is 4 x 4 m. At 10 x 10 m spacing, agricultural intercropping is possible, for example, interplanting with millet, beans, or groundnuts.