Van tuiniers naar klimaattuiniers. Burgers motiveren voor klimaatvriendelijk tuinieren.

What if… two simple words could open a novel way of looking at climate change adaptation? This dissertation investigates how private domestic gardens can be mobilized as a collective resource for climate change adaptation. In a period of increasing heatwaves, floods, and droughts, responsibilities for adapting to climate change impacts remains ambiguous. It is unclear whether citizens or governments should act, and citizens often doubt whether individual actions can generate meaningful collective impact. The dissertation addresses a key societal challenge by examining this tension between individual behavioural change (the i‑frame) and changes in the systems of which individuals are part (the s‑frame): how to bridge individual behavioural change and public policy action in a domain characterized by private ownership, substantial autonomy, and limited regulation. Private domestic gardens in Flanders (Belgium) serve as an emblematic case to examine this tension between personal freedom and collective responsibility. These open spaces surrounding private residential properties are typically managed with substantial autonomy, while their potential contribution to climate change adaptation remains underexplored due to private ownership and policymakers' reluctance to intervene. Nevertheless, gardens offer citizens a tangible means of climate action and provide policymakers with opportunities for local climate change adaptation. This raises the central question of how policymakers can motivate millions of individual gardeners to engage in climate adaptive gardening practices. The dissertation argues that the cumulative impact of individual actions is crucial, conceptualised through a we frame, which captures both aggregated individual action and collaboration between citizens and policymakers, across the i-frame and s-frame. Grounded in behavioural public policy and guided by design thinking, the dissertation moves from imagining a utopian yet plausible gardenscape to empirically assessing what makes such a future socially and politically achievable, focusing on both citizens (i‑frame) and policymakers (s‑frame). Using an interdisciplinary multi‑ and mixed‑methods approach, the research generates behavioural insights into climate‑friendly gardening and citizens' support for policy instruments in private gardens. Furthermore, two behavioural interventions focused on depaving are evaluated for their effectiveness in increasing public support for hard policy instruments and strengthening local policy capacity. A framed infographic presenting climate change adaptation as a collective effort significantly increases support for stronger policy measures, while a large‑scale gamified media campaign fosters learning, experimentation, and agenda‑setting across municipalities and proves successful in establishing new social norms. Overall, this dissertation reframes private domestic gardens as public resources and levers for climate change adaptation that can be integrated into climate change adaptation strategies. By combining behavioural insights with policy design, it offers actionable pathways for governments seeking to activate gardens for climate change adaptation. Coherent policy mixes that combine soft and hard measures with behavioural techniques can address awareness, risk perception, knowledge, and personal norms. While softer instruments such as information provision and participation enjoy broad public support, stronger measures including regulation and taxation are more acceptable than often assumed, on the condition that governments act alongside citizens. Ultimately, with this evidence‑informed narrative of an achievable gardenscape I aim to inspire both citizens and policymakers by offering a new perspective on pathways towards a different future.