Increasing agricultural productivity among smallholders in developing countries remains essential to improving food security, and one potential avenue for this increase is through stimulating technology adoption. In this paper we combine rainfall data with household survey and field experimental data to assess households’ use and potential demand for a risky agricultural input in Tigray, Ethiopia. More specifically, we explore how average rainfall, rainfall variability, lagged rainfall shocks and risk aversion relate to inorganic fertiliser use at the farm plot level. Further, we analyse how these variables and exogenous price variation affect the demand for inorganic fertiliser at the household level. The findings are potentially important for the design of policies to promote agricultural production in semi-arid rain-fed agricultural areas with vulnerable populations facing rainfall risk and shocks.