In vegetable long value chains, products’ perishability requires to precisely plan production. Such planning has to respect middlemen (e.g., cooperatives or wholesalers) expectations: quantity and timing of supply. Besides farmers have constraints and objective including farm land, crop rotation, workload, and viable income. Middlemen agree with regular suppliers on a planned supply calendar, which is defined as coordinated and anticipated establishment of expected production (characterised by a crop, a volume and a timing). Planned supply calendar are defined several months in advance, before plantation, and are then usually adjusted depending on unexpected events (technical or commercial). However, in a context where disturbances become more frequent and intense, such routine adjustment may not be suited anymore. Our objective was to understand i) how farmers and middlemen usually adjust planned supply calendar to manage unexpected events, and ii) taking the example of drought, how major disturbances may challenge these routine adjustments. We then discuss how such short-term management leads to potential trade-offs with long-term goals. Our method is inspired by the “diagnosis of uses”, which aims at understanding the diversity of ways to address an issue in a concrete situation of use (Cerf et al., 2012). We implemented a diagnosis of crop planning to understand how farmers and middlemen plan production, what disturbances they face and how they manage it (or not). Our case study is located in the Roussillon plain (Pyrénées-Orientales, Southern France), a vegetable production basin mainly oriented towards long value chains, which underwent drought for the last two years. We conducted semi-structured interviews with 18 farmers, 6 middlemen and 2 advisors, following an iterative snowball sampling method. Quotes were inductively analysed to specify their topics. One key step in planning process is seedlings ordering, as it implies to make non-reversible choice involving a significant amount of money (several thousand €/ha). Crop development is then monitored by middlemen in order to anticipate changes in planned supply calendar. During harvest, middlemen can manage overproduction at a given period by finding backup outlets (rather selling, even at low price than not selling). In case of shortage in planned supply, middlemen can solicit unplanned suppliers. In a context of drought, interviewed farmers took different decisions, depending on farm resources, crops produced, and available information on water resource. Decisions taken included i) proceed regardless of risk, ii) cancel plantation or decrease planted area, iii) postpone plantation with hope that water will get available later, iv) prioritize crops already planted, and limit water use for non-productive soil management operations. Due to drought, middlemen face a risk of major supply shortage, which was managed by: i) buying a more important share of supply to unplanned suppliers located in another region not affected by drought, ii) one middleman committed to refund bought seedlings in case of a harvest loss, in order to encourage producers to take risk. The first strategy is a short-term disturbance management, and the second strategy seems to be emerging as a last resort measure, for cases where a crop central for middlemen cannot be sourced from other suppliers. Farmers adaptations to disturbances such as drought aim to reduce economic impact, but in case all regular suppliers cancel or decrease production, this would lead to significantly reduced supply for middlemen. Thus, middlemen seek to secure their supply by broadening their supply basin or sharing risks taken by farmers. The short-term coping strategies we identified may however be implemented at the expense of longer-term goals in three ways. First, reduced production leads to reduced gross margin, for both farmers and middlemen, which may not be viable, particularly if drought is to last more than one or two years. Second, when farmers limit water uses for non-productive operations, this preserves gross margin on the short term, at the expense of longer-term production since such operations are important for soil quality management. Third, mutual trust built on long term between middlemen and regular suppliers cannot be built with unplanned suppliers solicited by middlemen for short-term disturbance management. Recurring solicitation of unplanned suppliers can also affect regular suppliers’ trust. Our results thus call for a broadening of perspective on long term, to anticipate potential intense and long-lasting disturbances. References Cerf et al., 2012. Agron Sustain Dev 42(4):4