Pearl millet (Pennisetum glaucum (L.) R.Br.) is the major staple crop produced by subsistence farmers in the West African Sahel, but its panicle yield is low because of poor seedling establishment in low-nutrient soils. Seedball is a cheap seed-pelleting technique that combines sand, loam, seeds and optionally wood ash or mineral fertiliser as an additive to enhance early growth of pearl millet under infertile soil conditions. The aim of this study was to investigate the effects of seedball technology on pearl millet crop establishment and panicle yield on-farm under Sahelian subsistence conditions. Over 2000 on-farm (2015–18) trials were conducted in 65 villages of the Maradi region in Niger. Conventionally sown and seedball-derived pearl millet crops were grown by using ‘farmer-optimised' simple split-plot designs with three treatments: (i) farmers' practice as control; and seedballs (2.0 cm diameter, made from 80 g sand + 50 g loam + 25 mL water + 2.5 g seeds as standard recipe) that contained either (ii) 3 g wood ash or (iii) 1 g mineral fertiliser (nitrogen, phosphorus, potassium; NPK) as effective nutrient compounds. In 2016–18, participating farmers could opt for one of the seedball treatments. Panicle as well as stover yield data were collected and compared with respect to seedball type (wood ash vs NPK), sowing depth (shallow vs deep), sowing time (wet vs dry), weed management (complete vs partial), local soil type (texture range sand to loamy sand), cropping system (sole vs mixed), and farmer. Results showed that seedballs do not suppress seedling emergence. Seedball treatments produced fewer but longer and denser panicles. Wood ash-amended seedballs showed a higher panicle yield increase relative to their site controls than NPK-amended seedballs. However, the average panicle yield of NPK-amended seedballs was higher than that of the wood ash-amended seedballs. The treatment factors wet sowing, partial weeding, sole cropping and farmers showed higher panicle yield. The seedball technology increases pearl millet panicle yield by ∼30% in the Sahel; it is simple and based on local materials.