Culinary herbs- a blog by Suzanne Milner

Suzanne Milner discusses a recent Taylorlab publication by Libby Rowland on deficit irrigation

 

What are the effects of climate change? Whether you’ve heard about climate change from school, academic articles, the news or films like An Inconvenient Truth, The Day After Tomorrow, or even the season 10 “The Last Ball on Earth” episode of RuPaul’s Drag Race, you probably know about temperature; that in general the temperature is rising but in certain countries it will become colder. But what about water? Like temperature, it depends on location but in general water supply is decreasing. Sounds crazy given about 71% of the Earth’s surface is covered by water but that’s largely sea water that is too salty. If you think how dangerous it is to drink too much sea water, it doesn’t take a genius to realize your plants won’t like it either. Because of this climate change effect, many biologists are researching the effects of decreasing watering on plants.

In crops like fruit trees, many projects have found reducing watering not only saves water and therefore money for growers, but it often improves the quality of the crop too. In a recent paper published in Scientia Horticulturae, Libby Rowland of Taylorlab has reviewed available research on reduced watering in culinary herbs. But why do we care about culinary herbs? What even are “culinary herbs”? Culinary herbs are those used for cooking or eating, but there are many herbs that are not use for consuming- most of these are used for medicine or perfumes such as Arnica, St John’s Wort and Patchouli. We care about culinary herbs because we tend to use more fresh herbs in our cooking today. When I was a child, the only fresh herbs we ate were those my dad grew in the garden. All other herbs were dried and came in little pots that frankly smelled nothing like their fresh counterparts. But now-a-days you’d be hard pressed to find a grocers or supermarket that doesn’t have pots of fresh herbs. Because of this, there are billions of potted herbs being grown commercially around the world. Vitacress, a herbs and salads company that Taylorlab collaborate with in the UK produce 20 million pots of potted herbs a year- and that’s just one company in the UK. That’s in addition to all the fresh cut herbs you can buy in supermarkets now. With so many fresh herbs being grown, what will happen if less water is available for them?

Libby found that a lot of the available research, particularly reviews on reduced watering, doesn’t reflect our increased consumption of fresh herbs. Libby gathered research in her review and discusses what the various projects have found. Examples of the effects of reduced watering discussed include;

  • Increased antioxidants in basil
  • Increased vitamins in parsley
  • Increased oil yields in mint and lemongrass
  • Improved oil quality in coriander
  • Increased shelf life in coriander

 

This means reduced watering can make crops better for you, smell better, or last longer. As consumers, we want the things we buy to be produced as sustainably as possible, but we also want better quality products, so if watering less causes both it’s a win-win. But Libby also points out that the research on culinary herbs is very limited, and more research is needed before practices will change in the industry. For more detail, the paper is available to read online here but next time you grow herbs in pots at home, keep in mind you may not need to water them as much as you think.