In the short-food supply chain, retailers have to make critical decisions when choosing which farmer to buy the produce from. Moreover, planning for long periods of time further complicates this task. This work presents a linear program integrated in a rolling horizon to assist retailers in planning their orders from different suppliers and knowing when to place them. The model is developed to overcome the single-item, multi-sourcing, capacitated lot-sizing problem and plan the long-term orders for the retailer. When tested, the model successfully planned the orders, deliveries, and inventories of the different suppliers while minimizing the cost for the retailer. Finally, when tested for instances of increased complexity, the model managed to find the solutions within an acceptable execution time.