On-farm seed priming is a simple technique that involves little or no extra costs, no risk, and little effort. Yet what it has to offer in the way of stronger, faster-maturing crops with better yields is simply enormous. Participatory methods can help farmers to realize the contribution this technique can make to their welfare, while ensuring that they use it properly—and widely. This guide offers an overview of the impressive results that have been seen to date using on-farm seed priming, and the implications they have for improving a range of crops that farmers in the semi-arid tropics depend on for food and income. This guide offers an overview of the impressive results that have been seen to date using on-farm seed priming, and the implications they have for improving a range of crops that farmers in the semi-arid tropics depend on for food and income.