Discussions of food sustainability often mentions seasonality, but, what is it and why is it important? Ros, our social media coordinator, explains, before providing 4 top tips for shopping and eating sustainably.
What do we mean by seasonal?
For fruit and vegetables to grow, a set of specific climatic and soil conditions are required. These conditions differ for different plants, with produce availability varying geographically and at different times of the year. When referring to seasonality, we mean the period of the year when produce is harvested. For example, in the UK apples are seasonal between July - October, and oranges are never seasonal from the UK as they require hot, dry summers such as those in Italy, Greece, or Spain (Futch and Singerman, 2018).
There are two types of seasonality: local seasonality and global seasonality
Local seasonality refers to food that is harvested and eaten locally during the natural growing season of a given region.
Global seasonality refers to food that is produced during the natural growing season in one region but is not consumed where it is locally harvested (DEFRA, 2012).
What is the Environmental Impact of Seasonal Fruit & Vegetables?
Methods for food production have significant contributions to the carbon footprint of the foods we consume, and can be larger than those linked to transport. Fruit and vegetables that are grown in the natural season will have the lowest inputs, and hence the lowest carbon footprint.
Take tomatoes for example; they can grow in the UK, but commercially often require a heated greenhouse even in the summer as the temperature is not quite warm enough. However, in Spain, they can be grown in polytunnels and open fields due to the ideal temperatures and solar intensity in the summer (Edwards-Jones, 2010). The use of climate-controlled greenhouses do have benefits, for example leading to higher yields, lower land use intensity and lower pesticide use. However, production by this method is linked to higher greenhouse gas emissions through energy used in heating and lighting (Karlsson, 2011). Hence, it is better to import the tomatoes from Spain in their natural season than locally from the UK as tomatoes where they do not have a natural season (Edwards-Jones, 2010). Seasonality, therefore, matters in discussions of food sustainability.
Additionally, eating seasonality can reduce emissions associated with food storage. Apples have a long shelf life when stored at temperatures below 5 degrees Celsius, however, storage at this temperature requires refrigeration which is associated with a higher carbon footprint (Edwards-Jones, 2010).
Again, as with many dimensions of food sustainability trade-offs emerge; is it better to export foods grown during natural seasonality, or to store and refrigerate produce that is locally grown out of season? If we consider the carbon footprint of potential food waste, does this change the equation too?
Top Tips for Shopping and Eating Seasonally
1. Get familiar with your country's fruit and vegetable seasonality
There are so many wonderful resources out there that you can use. The one we would recommend and use ourselves is the Scotland Food & Drink Seasonality Calendar available free for all here: https://foodanddrink.scot/resources/seasonality-calendar/
2. Shop at your local farmshops, farmers markets, & independent stores.
Although supermarkets will have seasonal fruit and vegetables, it can be hard to decipher between what is in season and what is not. Furthermore, what is in season is sometimes imported adding in extra complexities in trying to eat according to local food seasonality. Farmshops, farmers markets, and independent stores, are a good shout to check out as they often stock produce that has been locally grown and in season.
3. Be more open to diversifying your food
To eat seasonally, you will have to sacrifice eating the fresh strawberries all year round, or treating yourself to some asparagus in December. However, don't view this as a limitation- there are so many great fruits and vegetables available across the year including butternut squash in the autumn, or cabbages in winter. Diversifying your food, in addition to spicing up recipes, also has benefits for your health and wellbeing!
4. Grow your own food.
This can be one of the best ways to learn about seasonality. Whilst it takes a lot of work and you have to learn from your failures, harvesting produce that is fresh and home grown is so rewarding! You don't need a veg plot or even a garden, you can always grow things in pots on your windowsill. A great resource to help you get started is the Vertical Veg: http://verticalveg.org.uk/ten-great-crops-to-grow-in-containers/
DEFRA (2012) Understanding the environmental impacts of consuming foods that are produced locally in season. Project FO0412. http://randd.defra.gov.uk/Default.aspx?Module=More&Location=None&ProjectID=16390
Edwards-Jones, G (2010) Does eating local food reduce the environmental impact of food production and enhance consumer health? Proc Nutr Soc 69, 582–591.
Futch, S., & Singerman, A. (2017). Inside Spain’s citrus industry. https://crec.ifas.ufl.edu/extension/trade_journals/2018/2018_july_spains.pdf
Karlsson, H (2011) Seasonal Vegetables: An Environmental Assessment Seasonal Food. https://nmbu.brage.unit.no/nmbu-xmlui/bitstream/handle/11250/189423/Hanna Karlsson.pdf?sequence=1
MacDiarmid, J. (2014). Seasonality and dietary requirements: will eating seasonal food contribute to health and environmental sustainability? Proceedings of the Nutrition Society, 73(3): 368-375. Doi: 10.1017/S0029665113003753