In her doctoral thesis, Siv Mari Aurdal has evaluated the effect and potential of alternative growing media for versatile plant production based on compost from sludge digestate and garden waste, as well as the incorporation of wood fiber.
She concludes that the effectiveness of these peat-free and peat-reduced growing media varies significantly depending on plant type, growth phase, and cultivation method. The findings indicate that their use has limitations in terms of physical structure and chemical properties that can negatively affect plant growth.
Although some peat-free mixes, especially those combining compost and wood fiber, showed promising results under certain growing conditions, the research points to significant challenges associated with their use in versatile urban horticulture. Physical properties, plant uptake of specific plant nutrients and possible heavy metal contamination are some.
Furthermore, the studies show that combinations of compost combined with Fibergrow® wood fiber can potentially improve the properties of the growing medium, but do not achieve as good results as using peat as the main component or in mixtures with compost.
This supports the need for further research to optimize alternative growing media for versatile horticulture and overcome regulatory and practical barriers, which is crucial to promote sustainable horticulture in the urban environment.
The doctoral thesis adds to the knowledge on the use of alternative growing media for urban horticulture, which has a strong interest in adopting environmentally friendly resources. In particular, the results can help inform decision-makers about potential challenges associated with the use of such materials so far.
Aurdal's research can also help to reduce the dependence on limited resources such as peat and mitigate the environmental impact of waste, while maintaining the productivity and sustainability of horticulture. In a broader context, the research can also contribute to a more sustainable management of natural resources and waste, and promote the transition to a more environmentally friendly horticulture.
On May 3, 2024 at NMBU, Siv Mari Aurdal will defend her thesis entitled "Alternatives to peat as growing media for urban horticulture".