Protected cropping in organic systems (OGA)

Chair:Roger Hitchings (OGA)

Results from the international BioGreenhouse project and different perspectives from research and practice on the sustainability of protected horticulture production.

Session summary

The international COST Action BioGreenhouse is producing a large number of fact sheets for organic protected cropping systems; they will be available on the project’s website ( from 11th April 2016. Action Chair Rob Meijer from Wageningen Research (WUR) in The Netherlands added that around the same time, practical guidelines and books will be published on soil fertility, composting and compost use in protected cropping. Lucia Foresi (CAWR) reported on her experiences in conducting one of the Short-Term Scientific Mission (STSM) supported by the project. This one focused on environmental impact assessment tools for organic greenhouse horticulture.

The talk by Pete Dollimore (Hankham Organics) was very instructive on how to increase the diversity and number of beneficial insects for the management of pests in organic greenhouses. He states for example that the use of BT (Bacillus thuringiensis) only becomes necessary in his greenhouse from about November, once the parasitic wasp is no longer very active. One major feature for attracting beneficials is the use of flower and nectar strips along the beds in the greenhouse, bringing them directly to the crops and pests, as well as providing opportunities for overwintering (e.g. on Calendula!). He adds that keeping flowing coriander plants in the greenhouse is a perfect refuge and food plant for the parasitic wasp and many other predators. Before he finally removes the plants, he leaves them laying on the soil for a day or two, allowing the beneficial insects to migrate to other areas in the glasshouse, before he removes the plants. Also, aphid covered leaves of cucumbers for example, where a large proportion of aphids are parasitised (colour and shape change – see photo in presentation), are cut and brought outside to the field beans, so the predators can hatch there and parasitise more aphids.

Key conclusions

The discussion that followed the presentations brought out the following points:

  • Observation of plants, insects and soil is crucial. Take time for it!
  • In protected cropping systems we need to find man-made solutions for man-made situations (need to introduce and support beneficial insects in OGH all year round).
  • Biodiversity in greenhouses is the future, need to adopt practices to support them throughout their entire lifecycle (saving money on not having to buy new insects every year!).

Individual speaker presentations and abstracts

Rob Meijer (Wageningen UR): Biogreenhouse COST Action – Knowledge on organic protected cropping made available to the industry by European experts (874kb pdf file)

Rob Meijer

From 2012-2016 experts of 27 European and neighbouring countries work together within the framework of BioGreenhouse (COST Action FA 1105) to unlock and make available to the organic greenhouse industry – growers, suppliers, teachers and students- the latest knowledge and to contribute to the EU R&D agenda. Five working groups, being Robust Planting Material, Soil Fertility, Suppresiveness and Water Management, Crop Health, Energy Saving and Climate neutral production and Sustainability and Standards, are writing papers, leaflets and books for science and practice; about compost making, fertilisation, water management, sustainability tools, organic seed treatment, energy saving, crop health and food safety.

The Action will be finished in April 2016 at an international symposium from 11-14 April 2016 in Izmir(Tr) (www. There will be a parallel scientific and technical program. This symposium is open for everybody who is interested in organic protected cropping. At that occasion all this work, written in English, will be published and will be freely available.

Lucia Foresi (CAWR): Comparing the usefulness of assessment tools in evaluating the environmental impacts of organic greenhouse horticulture (160kb pdf file)

This presentation refers to the Short-Term Scientific Mission done at the Institute for Agrifood Research and Technology in Cabrils (near Barcelona, Spain), in May-June 2015, as part of EU COST Action FA1105 ‘BioGreenhouse’. The Mission’s main objective was to compare two chosen assessment tools, Life Cycle Assessment (LCA) and Public Goods tool (PGT), both in the form of Excel worksheets, to evaluate the potential integration between their data, so that the development of a single holistic assessment method could be planned. The presentation mainly highlights the methodological differences and potential common points between the tools, referring to a chosen case study (Tolhurst Organic, a stockfree horticultural farm located near Reading, UK) that was assessed with both, and then gives suggestions for further research in the future. While LCA gives quantitative results on impacts on key environmental categories, PGT shows ways to improve farming practices regarding a set of social, economic and environmental aspects through a simple scoring system. In this sense, trying to combine results from different assessment tools might be difficult because it emphasizes the lack of overall complementarity between them, but simultaneously it could be a useful starting point for an integrated discussion on production, use of natural resources and improvements of practices among decision-makers

Pete Dollimore (Hankham Organics): Bringing in the Bugs: How can local biodiversity be harnessed in our greenhouses? (2.53b pdf file)

One of the fundamental qualities of any good organic system is it’s ability to, not only exist alongside a flourishing natural ecology, but to utilise and enhance this potential powerhouse of stability and health.

The term ‘protected’ however immediately suggests a very different sort of cropping system. A degree of control can be exercised over environmental influences, which are tipped in favour of the crop. This inevitably leads to a strategy regarding the internal ecosystem and its interaction with the external.

Combining border controls with introduced biological agents may effectively regulate the establishment of pests in monocrop systems. However in diverse and continual cropping systems there is no ‘down season’ clear up and the balance of pest, predator and parasite has to be permanently balanced in favour of a viable harvest. Maintaining a healthy biodiversity inside as well as outside the greenhouse is needed to regulate a stable state of play. Examples and strategies for encouraging this, as well as situations where success has been varied, will be presented using case studies from the 0.7ha glasshouse at Hankham Organics as well as other mixed cropping protected systems.


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