Innovation

The innovation at SedumExtra is created by a small team of specialists who work from a nursery in Alphen in the Dutch province of North Brabant. Over many years, they have experimented on their own fields with plant mixes, substrate depths, and technical systems until they found combinations that are reliable on real roofs. Instead of only selling plants, they now prepare roof-ready packages that professional partners can install in a single step. These packages combine vegetation, growing medium, and drainage elements that are adapted to the carrying capacity and use of each roof.

When a project begins, SedumExtra first assesses the practical situation on site. Staff discuss the size of the roof, the structural limitations, access for installation, and the building owner's wishes. Based on this analysis, they select heavier or lighter systems, choose between sedum-dominated mats or more diverse mixtures, and plan the logistics in detail so that the material arrives at the right time. The company also invests in sustainable growing methods at the nursery itself, with careful water management and attention to biodiversity on the grounds, and continually tests which species cope well with a changing climate.

Through this approach, SedumExtra transforms unused roof surfaces into a climate solution that aligns with the daily practices of contractors and building owners. The ready-made systems help cities to implement measures that increase safety, resilience, and quality of life, which are key aims of SDG 11 on sustainable cities and communities. In every project, the company acts as a partner that translates abstract urban challenges into concrete choices about plants, systems, and logistics on a specific roof.

Inspiration

The inspiration behind this innovation starts with people. In the interview, Bart explains that “it was the team and the people that I spoke with that attracted me to work with” and that “they have awakened my interest in green roofs and sustainability.” His personal love for nature fits perfectly with this work. He says, “If you see my house, it's one jungle, so the connection is made easily.” For him, the project is meaningful because it combines daily contact with customers and colleagues with real, visible improvements in the environment.

Bart also tells how the founder, Hans, made a radical change in his life. “Hans used to be a chicken farmer and he wanted something else.” While searching for a new direction, he came into contact with the sustainable movement and green roofs and started experimenting on a small scale. Those early trials grew into a specialist nursery that now produces large amounts of sedum every year. The drive to continually develop better products and techniques stems from the desire to address climate issues such as heat, water scarcity, and biodiversity loss in urban areas.

Underlying this is a clear set of values. SedumExtra wants “to make sustainability… available for all customers,” not only big companies. Bart says their focus is “to give a high-quality product for the best reasonable prices” and to give advice so customers achieve good results with their roofs. His message to other businesses is simple: “Don't only focus on the economic side,” and “give back to your local community by participating in the local community.” This mix of personal passion, bold choices, and social responsibility shapes the innovation and its contribution to SDG 11.

Overall impact

The innovation at SedumExtra already shows a clear impact on both the company and the cities it serves. In a little more than ten years, the business expanded from approximately two hectares of production to around fifty hectares, resulting in roughly five hundred thousand square meters of sedum being produced annually at the nursery. Each square meter of green roof retains, on average, between 20 and 25 liters of water. Together, these numbers demonstrate that the solutions are being applied on a large scale and that they are making a measurable difference in terms of water retention and biodiversity in urban areas.

In the short term, the effects are directly visible on the roofs and in customer reactions. Clients send photos and compliments about how their roofs look and work, and they proudly share the results of their projects. SedumExtra supplies not only plants but also all the materials needed to install a functioning green roof, so every project immediately contributes to buffering rainwater and creating habitats for insects in places that would otherwise remain hard and grey. The personal contact that Bart describes with customers and transporters also means problems are solved quickly, and projects can continue smoothly.

In the long term, the innovation enhances both urban resilience and the company's social role. The growing production volume increases the total area of green roofs, which supports the goals of SDG 11 on sustainable cities and communities. At the same time, SedumExtra builds strong ties in its own region through tours for local senior groups and sponsorship of clubs and events. This demonstrates that the impact extends beyond ecological and economic benefits to cultural aspects, as the nursery becomes a visible and active partner in a greener community.

Business benefit

Because SedumExtra chose to focus on sustainable green roofs and continued to develop its products, the company has experienced significant growth. Bart explains that the nursery started with about two hectares a little more than ten years ago and now grows around fifty hectares, about five hundred thousand square meters of sedum per year. This increase in production volume demonstrates strong demand, making it possible to relocate to a new building and supply many more projects each year. The innovation in growing methods, such as reducing chemicals and testing new ways of fertilization and irrigation, also protects product quality and supports long-term customer trust.

Because SedumExtra supplies all necessary materials for a working green roof and offers practical advice, customers experience clear value and respond very positively. Bart says clients send emails with pictures, share compliments and proudly show finished roofs with SedumExtra products. The company aims to offer high-quality products at reasonable prices and to help customers maintain their roofs to achieve the best possible results. This combination of service and performance likely strengthens customer loyalty, encourages repeat orders, and helps SedumExtra gain a role in bigger projects and more diverse product lines, such as evergreen plants for gardens.

Because the business also invests in its local community, its reputation and network grow in tandem with its sales. SedumExtra hosts tours for local senior groups, sponsors sports clubs, and takes part in local events. Bart notes that this cultural impact matters to the company as much as economic growth. These activities make SedumExtra a visible and trusted partner in Alphen and the wider region, which supports employee pride, attracts new partners, and reinforces its position in the market for solutions that support SDG 11 on sustainable cities and communities.

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Social and environmental benefit

SedumExtra’s innovation benefits society and the environment by turning empty roofs into active green spaces. On every project, their systems help retain rainwater on the roof instead of sending it all at once into the sewer. In the interview, Bart explains that one green roof can hold around 20 to 25 liters of water per square meter. That means that in heavy rain, many square meters of SedumExtra roofs reduce peak runoff and lower the risk of flooding in streets and neighborhoods. At the same time, the plants insulate the roof, so buildings stay more comfortable during warm periods and use less energy for cooling.

The environmental impact goes further than water and temperature. SedumExtra grows sedum and other plants that create extra habitat for insects and birds in places that would otherwise stay hard and grey. The biodiversity mats and mixed vegetation support pollinators, adding variety to urban nature. In their own nursery, they strive to grow with as few chemicals as possible and experiment with mechanical weeding and even a robotic weeder. By constantly adjusting fertilization, irrigation, and growing methods to suit weather conditions, they work on a product that is both robust and as sustainable as possible.

For society, the benefits are evident in daily life within and around the city. Residents, employees, and visitors look out onto green spaces instead of bare roofing, which enhances their overall experience of the environment. Locally in Alphen, SedumExtra invites senior groups for tours and supports clubs and events, which strengthens the bond with the community. The company also aims to keep green roofs accessible for smaller customers by offering high-quality products at reasonable prices. In this way, their work supports the goals of SDG 11 by improving safety, comfort, and quality of life in and around cities.

Interview

Bart, Operations Coordinator

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