Sub-Saharan Africa experiences poor soil fertility that suppresses crop yields. The use of fertilizers has therefore been recommended as one of the ways to address this problem of low yield and poor agricultural productivity. Maize fertilizer use in Ghana, for example, is low in general but highly variable with yield responses varying across agroecological zones. Therefore, soil fertility may not be the only culprit for low yields and variability, as climate could be a contributing factor as has been identified in recent studies for Ghana. FERARI is undertaking trials on fertilizer yield response for Maize, Rice and Soybean across agroecological zones in Ghana, which have varying climatic conditions. We therefore seek to explore the influence of weather on the potential and water limited yields of crops by simulating the daily growth and yields using soil and climatic variables.