Winter Harvest: the Green Revolution

News

Seasonal and sustainable winter vegetable production in Central European climates appears contradictory and represents formidable challenges regarding increased resource efficiency and reduction in greenhouse gas (GHG) emissions. Europe’s ‘Roadmap 2050’ emphasises the importance of finding new ways to reduce resource inputs and develop new products which will help to support the shift towards a resource-efficient and low-carbon economy. Consumers increasingly demand fresh, high quality vegetables that are seasonally produced by local producers. In winter months, the demand is met by energy-intensive production systems requiring considerable fossil fuel energy for heated glasshouse technologies, as well as by importing products with long-distance transport requirements that majorly contribute to global warming.

Leafy kale grow in open field in winter. Ornamental kales look very attractive and can be marketed in December for high-end gastronomy. Photo: Palme

Oriental Greens are well adapted to unheated winter production. They are extremely frost hardy, fast growing and delicious in taste. Photo: Palme

It is almost unknown that even common lettuces withstand temperatures down to -11°C. Photo: Palme

It is as easy as it is extraordinary: many vegetables crops are much more frost hardy than they are supposed to be. They can be grown in unheated greenhouses during wintertime. In 2007, Wolfgang Palme started a research project in Austria at the Horticultural College and Research Institute, close to Vienna. He discovered that lettuces can withstand temperatures below -10°C and Japanese greens even -20°C. His trials treated a diversity of more than 70 different crops that were well suited for sustainable unheated winter production for a local fresh supply. Lettuces, radish, kales, onions and carrots are attractive winter crops for the fresh food market.

In the Core Organic Project GREENRESILIENT, trials are carried out to answer the question of whether or not this production system is also suited for other Central and Northern European countries. Crop rotations are designed for sustainable and low-energy growing systems. Northern countries lack light during the cold season. Timetables are needed that show sowing and planting dates for a local fresh winter supply all over Central and Northern Europe. Therefore, research stations in Switzerland, Belgium and Denmark are involved.

There is no doubt that we need a resilient and solid year-round local fresh supply of organic vegetable crops in the different climate zones of Europe. This project will help to make that possible.