Harvesting and post-harvest handling

When the millet is mature and dry enough for harvesting, the grains pop out cleanly when the head is pinched. At this point, harvesting can commence. Millet is harvested manually using a knife or sickle. The panicles are harvested into baskets or bags and stored on a wooden rack to dry before they are threshed. The stover is also harvested and stored for fodder, however in some cases the millet stalks are left standing in the field and grazed by animals during the dry season. Proper post-harvest handling of organic millet aims at maintaining grain quality, minimizing losses and avoiding any contamination risks from extraneous materials and agents. The post-harvest handling process starts with proper and timely harvesting and drying.

In Africa millet is usually harvested by hand by picking the panicles or harvesting the whole plant. Harvesting may be done several times, as panicles ripen unevenly in some varieties that produce many tillers. The crop is harvested, when the panicles are fully mature and the plant is nearly dry. To avoid unnecessary grain loss to birds or lodging caused by the storm, the grain should be harvested as soon as seed maturity is reached.

The harvested panicles are dried in the sun on a mat, on a tarpaulin to minimise ground contamination or on a raised platform, and in a fenced area to keep off domestic animals. The drying panicles should be protected from rain to avoid delay of drying and development of mould. Drying of the millets at temperatures of about 21 °C reduces reproduction of storage pests. The ideal moisture level after drying should be 12 to 13 %.

Threshing is mostly done manually by beating the panicles packed in jute or sisal bags. With this method, care should be taken not to damage the grain. After threshing, grains are winnowed to remove any foreign matter. Threshing machines for millet also exist.

Millet grains store very well; the grains can be kept for longer time than maize and sorghum grains. If stored adequately, grains kept for seed can remain viable for several years. To reduce losses at storage the grains should be dry and clean. To avoid damage by the lesser grain borer and the khapra beetle millet seeds should be stored in sealed spaces or containers like in drums and at cool temperatures, for example underground. Alternatively, the millet heads can be hung over kitchen fires to repel storage pests with the smoke. If stored on the heads, the glumes protect the grains to some extent. To prevent movement and dispersal of insects, the millet seeds can be mixed with inert substances such as sand and wood ash. These substances fill the enclosed spaces and act abrasive enhancing water loss through the insect cuticle and thus killing the insects. Seeds can also be mixed with repelling plant materials such as leaves of Boscia senegalensis, and mint, Hyptis spp, and pulverised pepper.

Ratguards should be used to prevent entry of rats into the granaries. Stored grain can further be brought out periodically and exposed to the sun in order to reduce the build-up of high humidity conditions, which is a precursor for mould development. Exposing the grain to high sun intensities also kills pests, e.g. moth larvae and weevils.