Household driven and council managed street greening: scoring cost, expertise, space, and cost-benefits of green infrastructure combinations

• Systematic mapping of common GI across 112 UK cities identified 80 configurations. • GI costs range from £2.5/m² for grass to £248/m² for combination with green walls. • Household GI combinations covered areas from 4 to 80 m². • Economic benefits can reach ∼£800 per m² yearly with efficient GI configurations. • DIY scores show cost return is higher for household GI than for street scale. While extensive research has documented the environmental benefits of green infrastructure (GI), do-it-yourself (DIY) approaches that empower individuals and communities to implement small-scale green solutions have received limited attention despite their potential to democratise urban greening and foster community engagement. This study aims to systematically characterise DIY GI implementation across UK cities and analyse the costs and benefits of GI establishment. We conducted mapping of GI configurations across major UK cities using Google street view imagery and field observations, identifying 30 street-scale and 50 household-scale GI scenarios, complemented by an extensive literature review examining small-scale GI interventions. This focus on household and streetside GI provides insights into small-scale interventions, although larger spaces such as urban forests, parks and grasslands also provide benefits, they are beyond the scope of this study. A five-level scoring framework was developed for costs, space requirements, expertise levels, maintenance demands, and cost-benefits to design DIY guidance cards for GI scenarios. Our findings reveal diversity in GI adoption, with street trees and basic grass combinations dominating street-scale implementations (20.8 % each), while household-scale approaches show remarkable variety ranging from simple grass-only configurations (18.5 %) to complex multi-feature systems. The analysis identified a linear relationship between higher GI establishment costs and increased maintenance costs, despite greater variation in the latter. The detailed DIY score reveals that household-scale combinations have greater variation in cost and higher potential benefits compared with street-scale interventions, which remain clustered at lower scores despite higher space demands. The DIY framework enables local authorities and households to make informed GI decisions, addressing key implementation barriers. Aligned with UK policies for GI, the current framework can be further enhanced through interactive platforms, planting schemes, and added metrics for biodiversity and climate adaptation.