The term nature-based solutions (NBSs) is understood as a multidisciplinary umbrella concept that includes aspects such as green/blue infrastructure and urban gardens and forests. However, the important question here is what features of ecosystem-based approaches are essential for them to be considered nature-based? This study aims to answer this question by analysing the potential of allotment gardens (AGs) to be considered as NBSs. To do so, the possibilities and obstacles regarding a Polish case study were analysed based on the following six research questions: (1) How do AGs use blue and green infrastructure? (2) What problem(s) do AGs solve today? (3) What kind of benefits do AGs provide? (4) Do AGs possess implementation and management capabilities? (5) Can AGs be treated as economically efficient? (6) What are the advantages of AGs versus other possible solution(s)? With regards to obstacles, the study has identified: institutional barriers, irregular distribution of benefits, and deficiencies in economic efficiency. Nevertheless, AGs together with other historical urban green/blue infrastructure may be regarded as a kind of unsophisticated NBS, the effectiveness of which is limited. These solutions may be created as independent structures or (historical) green/blue infrastructure may be enlarged, fitted out, linked, and improved to implement NBS projects.