Effects of Planting Dates in Farming Systems in Ghana: A Review

In Ghana, planting-date decisions are increasingly constrained by delayed rainfall onset, frequent false starts, rising dry-spell intensity and shifting agroecological boundaries. Although individual studies have examined crop-specific responses, a consolidated synthesis linking climatic variability with planting window reliability across zones has been limited. This review addresses this gap by analysing evidence on rainfall onset behaviour, intra-season moisture patterns, crop physiological sensitivity and farming system interactions to determine how planting dates influence establishment and yield outcomes in Ghana’s rain-fed systems. A narrative review approach was applied, drawing on empirical field studies, climatic analyses, intercropping trials and modelling assessments in the reviewed literature. The synthesis shows that compressed and increasingly unpredictable planting windows affect all agroecological zones, with the Guinea Savannah and Transition zones exhibiting the highest sensitivity owing to unstable onset and prolonged early season dry spells. Key crops, particularly maize, sorghum, cowpea and upland rice, experience substantial yield losses when planting is misaligned with early season moisture. Labour constraints, equipment limitations, weak advisory integration and the persistence of false rainfall start further restrict farmers’ ability to plant within optimal windows. These interactions also influence nutrient uptake, pest dynamics and intercrop competition, demonstrating that planting dates operate as system-wide risk factors rather than a single management decision. Overall, this review underscores the need for high-resolution planting date datasets, calibrated crop models and advisory systems that combine rainfall onset probabilities, soil moisture thresholds and indigenous indicators to support more dependable planting recommendations across Ghana’s changing agroecological landscape.