How to build Floating Islands naturally – bringing back the fantastic lost art of Chinampas!
Recently we ran a Permaculture Design Certificate – Water Module workshop in partnership with Growing Roots Permaculture at the amazing Starseed Gardens where participants learnt how to build a natural floating island. The floating islands were planted with a variety of species that play different roles. Floating gardens are super productive and support nutrient dense plants such as water cress which is a superfood, water spinach and kang kong an asian green. We also planted vetiver grass and carex grass which provide a floating wetlands effect via biofiltration with their larger roots, taking up excess nutrients present in the water. The word Chinampas comes from the Nahuatt word for “square made of cane”, so if we take this as our guide, harvesting bamboo, cane or similar material is a way to get started.
Materials harvested onsite at Starseed Gardens included bamboo and camphor laurel which is a weedy tree and these two core materials provided floatation, lashed together with hemp rope. The camphor laurel had dried out to provide better buoyancy. Reeds and sugar cane were harvested and dried out on site, and coconut husk was sourced from locally sold coconut water. The coconut husks were laid out on the ground and a tractor slasher run over it to break up the husks into useable coconut fibre, perfect as a planting media. The reeds provide significant carbon source, and the sugar cane provides trace amounts of sugar which accelerates plant growth. Dan Schreiber has been experimenting with aquatic plants and substrates for many years at Starseed Gardens. When Dan and Tom met there were many discussions about what the best way to design the floating islands, floating gardens and floating wetlands would be.
Through collaborative design process and foraging for suitable bio-materials, several designs presented themselves quite organically. All the bio-materials are representative of what is typically available in many sub-tropical and tropical climages. Together the bio-materials provided the appropriate plant growing medium and biofilm host, to support the transport of nutrients from the water into the plant roots, as well as natural floatation. These materials were assembled in a design led by Dan Schreiber (pictured above far left) and Tom Duncan (pictured above 2nd from left) collaboratively to build a natural floating island capable of growing food, and biofiltering excess nutrients out of the water.
As part of a cumulative Chinampa system evolution, over time the floating islands will sink, potentially after 2 years, and over that time will have provided an abundant harvest of food crops (up to 2 – 10x the productivity of conventional land based growing systems), whilst also biofiltering the water and providing sub-surface aquatic habitat. Permaculture design seeks to build elements that are multi-functional and serve multiple needs simultaneously. Floating gardens, wetlands and islands that can transition to Chinampa systems in ponds, dams, lakes and canals is a good example of the type of innovation that is needed in the face of climate change and building resilient communities whom are disadvantaged and exposed to water level rises. Many disadvantaged communities around the world inhabit low lying areas and drainage ares or steep hilly terrain because many planners know of the risks of living in these types of locations.
For communities in low lying and flood exposed areas, floating islands combined with adaptable