Among their specialties are green roofs and the ready-made roof garden, which can be fitted in just one day. They also create complete gardens on the roof, and offer the lightweight ‘Donordak’ made from used grass turf, which insulates and extracts cO2 from the atmosphere.

Most of their two dozen roof gardens are private, but you can visit the one they built for Milieucentrum amsterdam at the Botanical Garden on plantage Middenlaan.

This and more inspiring projects can be found in the print copy of A smart guide to Utopia or the ebook version.