Why spend a fortune on fancy plant boxes when you can grow your vegetables safely in free building plastic waste? In the project From Building Waste to Building Gardens, we kill two birds with one stone. We extend the life of the old construction products before they are sent to recycling. Construction products are given a new function as plant boxes. In doing so, we are saving the climate of unnecessary strain and we support the development of urban agriculture, which means cheaper, fresher and more sustainable vegetables.
PVC is the most widely used plastic material in building and construction. Pipes, gutters, roofing sheets, cable trays, windows and doors are made of so-called rigid PVC, which is the material we here propose to be used in urban agriculture.
PVC is made for water
PVC building products are particularly suitable for growing in because the construction products are designed to come into contact with water. Comparing the rigid PVC with wood, for example, is has a considerably longer life. PVC does not rot and can last for over a hundred years. For this, the material is easy available , which means that if you want to build a city garden using PVC building waste, then the material is very easy to transport from the recycling site. It can easily be done for example on a loading bike.
PVC building materials in rigid PVC are distinguished by being collected and sorted for recycling. In Denmark for example, we have a statuary order that requires that this happens. This means that building waste in PVC is found at almost all recycling sites. The material is thus easily accessible to everyone. The idea is that the building materials are reused before they are recycled.
Free construction waste for urban agriculture
In the project, we extend the life of the materials by giving the construction products a different function in the form of plant boxes for urban agriculture. The main advantage of using PVC building waste to build an urban garden is that the waste is easily accessible and accessible to everyone for free. High costs for plant boxes are not necessary.
If you no longer want to grow your urban garden, the used waste must be handed over to the local recycling center, from which it will be sent for recycling. So after being used for urban gardens, the construction waste can once again get new life in the form of new pipes, new gutters, etc.
The environmental and climate benefits of growing in PVC building waste can be found elsewhere on this site. Likewise, you can find information on health topics related to using PVC in urban gardens; here you will see that it is without risk to grow in PVC building waste.
Is it safe to grow vegetables in plastic building waste? Is it safe to do it in the city where air quality might be poor? Those are the fundamental questions to ask yourself before you start urban gardening.
Safe gardening in the city
When you grow vegetables in the big city, it can hardly be avoided that the crops absorb unwanted substances from soil and air. However, the quantities are so small that it is not harmful to health. As associate professor Jakob Magid of the Department of Agricultural Science at the University of Copenhagen says: “When the general health risks of living in a big city are considered, the risk of eating city-grown vegetables is negligible … In an overall perspective, it is without a doubt beneficial that people grow their own vegetables. It provides fresh air, exercise and reestablishes the connection to how food is produced. These benefits must be weighed up against an extremely little risk.”
Absolutely no risk associated with rigid PVC waste in urban agriculture
To be on the safe side, we have asked a toxicologist about the safety of growing vegetables in discarded PVC building products,
Rigid PVC construction waste is normally divided into three waste categories: production waste, which is generated at manufacturing plants and often recycled locally; installation waste, which comes from the construction sites; and post-consumer waste. When it comes to the post-consumer products, there may be waste that contains a small percentage of heavy metals. To achieve long product life, for instance, lead compounds were added as stabilisers before 2015. These compounds, however, are so embedded in the PVC plastic that they are not released to the environment. Among other things, this has been shown by the Danish Environmental Protection Agency in a study, in which I personally participated, where drinking water was analysed after flowing through 30-40-year-old underground PVC pipes. Thus, there is absolutely no health risk associated with reusing PVC products containing heavy metals in urban agriculture.
Dr. Lars Blom, toxicologist
Source: The Danish Environmental Protection Agency: ”Field study of water supply pipes in plastic,” Environmental project no. 1049, 2005, https://www2.mst.dk/udgiv/publikationer/2005/87-7614-863-7/pdf/87-7614-864-5.pdf
From Building Waste to Building Gardens is a project supported by VinylPlus®, the European PVC industry’s voluntary commitment to sustainable development. In the project we develop and test urban agriculture systems with reused PVC building waste. Project manager is architect Maja Sønderskov and assistant is Marianne Mikkelsen. The PVC Information Council DK is also affiliated with the project with director Ole Grøndahl Hansen and communication consultant Tobias Johnsen. However it is the volunteers who cultivate and water the plants on the various hubs around the City of Aarhus that make it all run. Our partners include Samskab Aarhus, Gallo Gartneriet, GroSelv and Skraldecafeen.