The recent hot days will be disastrous for the lettuce yields during the next two weeks, says Johan Desmet, who grows various types of lettuce in a 5-hectare hydroponic greenhouse in Izegem, Flanders. Colleague lettuce grower Geert Van Hulle also encountered problems.

Desmet estimates his loss of income at up to 50 percent for this and next week, due to failure and loss of quality. “Lettuce cultivation gets into trouble when the temperature in the greenhouse exceeds 40 degrees Celsius, and that happened four days in a row last week. The consequences are now noticeable.”

Besides lost crops, the loss of quality is what Desmet fears the most. “That is not good for the customer. I prefer delivering less but good quality rather than vice versa.”

Summer bad
The harvest disrupted by the heat is yet another setback for Desmet this summer. Although June, July and August are the best months for lettuce, this year it is not going well. “Prices have been disappointing so far. This is, among other things, due to the large supply,” he says.

Last week, the clock in Belgium recorded 31 cents for head lettuce, Desmets main crop. "While the prices two weeks ago were only just 15 cents," the grower sighs. According to him, a price of 35 cents is the minimum necessary to earn a decent living. Due to the heat damage, the grower from Flanders is expecting a price increase in the coming weeks. But due to the loss, he can hardly profit from this.

In contrast to the bad summer, Desmet did have a good spring. “The coronavirus has had no negative impact on our business. Our products go to retail and due to the lockdown, sales from retail went very well.” The good sales translated into relatively good prices, also because the competition from outdoor cultivation in spring is less.

Lettuce cultivation for the hotel and catering industry
Geert Van Hulle was more affected by the corona crisis. The lettuce grower from Veldegem, who together with his son Alfons grows twelve different types of lettuce under 2 ha of glass and on 1.5 ha of open field, supplied exclusively to the hotel and catering industry. Due to the lockdown, this sales market completely disappeared in March and April and the harvest had to be destroyed. For the destroyed crop he was partly compensated through a government arrangement.

The closure of the hotel and catering industry was the reason to complete the transformation to organic cultivation, a process that was started last year. Because of the coronavirus, father and son also examined their sales channels and they decided to supply to retail as well. “We are now working with Bio-Planet and that is actually going well. They even purchase more than originally agreed.”

The organic lettuce is currently being sold as conventional product. “only after growing organic for two years, you are allowed to sell under that label,” explains the grower.

Since the reopening of restaurants and cafes in June, sales to the hotel and catering industry have also started again. However, there is no question of a full recovery. “Sales are at approximately 80 percent,” says Van Hulle, who works with fixed prices. “2020 is a year to forget quickly. We will never be able to recoup the loss of March-May,” according to the grower.

Heat sensitivity varies per type of lettuce
He too has been bothered a lot by the heat. “At temperatures above thirty degrees it is difficult to keep the heat outside the greenhouse, especially if it does not cool down at night, and last week that was the case. The danger of the heat is that plants shoot early and that freshly sown lettuce does not emerge.”

Van Hulle, who grows various types of lettuce, including head lettuce, arugula, Lollo bionda, mustard herb, frisee, mizuna, golden streak and tatsoi, says that heat sensitivity varies greatly. “With head lettuce there is less loss than with oak leaf varieties, wher the loss can be up to twenty percent”, he cites some examples. Lambs lettuce is the biggest risk group in warm weather, he says. "That actually is a winter crop and cannot withstand heat."