Market interventions such as price supports or fertilizer subsidies can lead to gains from speeding up adoption of new technologies, but the policies distort resource allocation. A framework is developed for optimizing policies in light of the adoption‐allocation trade off. Based on adoption coefficients and production parameters from third world agriculture, levels and duration of policies are estimated. Sensitivity analyses are performed. Gains are small at best and may be zero or negative in view of farmer costs of adjustment and deadweight losses from taxes.