Main objectives of the challenge




Closing nutrient loops: designing a new composting unit

  • The compost can act as the stomach of the farm, where green waste is turned into new nutrients, creating a circular system. Botildenborg is far from being self-sufficient in compost, and they currently buy municipal compost made from the green waste of the city as well as organic fertilizers based on seaweed. In the social garden, nettle and comfrey water are also prepared and fertilised. 
  • The task is to develop functioning composting systems that can maximise the amount of compost self-produced within the farm and act as a pedagogical tool for groups working in the garden. 
  • The composting unit would be fed by both the cooked kitchen waste and the organic material generated within the farm consisting of old plants, crop residues, and organic substrates from microgreen production and mushroom cultivation. 
  • Botildenborg displays a smaller but functioning composting system in the social garden with a cold composting system and a small worm unit. 
  • The new composting unit will have to meet the requirements of being manually operated (to allow for realising workshops and training) and preserve the space's aesthetics and usability. As so many different groups use the garden, Botildenborg aims to showcase several ways a farm can compost waste so that the nutrients stay in the farm loop.


Create a system for water harvesting and minimize water use

  • Malmö often has wet winters and dry summers. Botildenborg site is exposed to sun and wind throughout the summer; therefore, one of the main challenges of Botildenborg is to find solutions that can maximise the capture of rainwater and minimise water use on crops, especially during the summer.

  • Currently, Botildenborg has installed six IBC (intermediate bulk containers) tanks capturing the water runoff from the farm building’s roof. However, an experienced problem was associated with the high rainfall during the winter (exceeding tank capacity in a period when water is not needed). A small pond is also present, which enables capturing the water run-off from the vegetable washing station and precipitations; water from the pond could also be used for irrigation. 

  • It should be noted that municipal tap water is used for washing vegetables during harvest season (April-November) for food hygiene reasons. The same applies to the irrigation of microgreen, mushroom and hydroponic cultivation units in shipping containers. The challenge here is to develop methods that can be used to maximise the use of rainwater and minimize the use of municipal water, as well as identify cultivation systems and strategies that can reduce water requirements, especially for what concern crop production in both the market garden and the social garden.