It’s not exactly babyleaf, but not a full head of lettuce either – it’s exactly in between: a lettuce variety that’s harvested between 80 and 120 grams. When the lettuce is cut just above the core, the heads immediately separate into a large amount of individual leaves and a minimum of waste is left. We’re talking about Salanova® Teenleaf, the concept that was launched by breeder Rijk Zwaan last year. The lettuce varieties that can be harvested when still young, don’t just offer benefits to consumers, as shown by cultivation trials carried out in the Proefcentrum voor de Groententeelt in Belgium. “We’re seeing that compared to babyleaf, we can realize a higher yield per square meter”, says Simon Willemen of Hortiplan. “What’s more, the Teens provide a better shelf life.”
“The Teenleaf concept responds to consumer demand for convenience. In recent years, we’ve seen an evolution in convenience products. Large heads of lettuce are less popular. The Teens products are more robust than babyleaf, but still forkable for consumers. The small cut surface and robustness of the leaves have a positive influence on the shelf life and are available in different colours, textures and leaf shapes.
This is according to Simon Willemen, business developer with Hortiplan, known for their mobile gutter solutions in lettuce cultivation. Rijk Zwaan asked the company to do a trial together with lighting specialist Signify, at the Proefcentrum voor de Groenteteelt in Kruishoutem (Belgium), in order to explore the production potential of the Teens. “We wanted to see if our yield estimates could actually be attained”, Simon says. “The first results certainly point in that direction.”
Saving space with mobile gutters
At the research center, a trial was set up on mobile gutters. As the lettuce grows, the gutters are moved further apart, so that each plant has enough space for optimum growth. “In order to grow as efficiently as possible, you’ll want to make the plant density as high as possible without limiting the plant growth due to lack of space. Working on movable gutters is a huge advantage there. Babyleaf doesn’t grow all that much in size, so such an installation has limited advantage there, but in whole-head cultivation it’s commonly used, because it enables one to be economic with space, thus increasing the production per square meter.”
For the teens, growing on gutters also turns out to be pretty beneficial. “The density can be increased quite a bit”, Simon shows. “That has two causes. Instead of letting the lettuce grow to 250-300 grams, as is done with whole-leaf, we harvest these ones at a younger stage, around 80-100 grams. That means the plants can be harvested at a higher density. Furthermore, we can work with narrower gutters because the heads remain smaller: 7 cm instead of 10 cm. These new gutters will be tested soon.”
All in all there’s a lot of potential, Simon thinks, and with the results from the cultivation trials looking good as well, he’s in a good mood. “The cultivation system is comparable with how you grow a whole-head, and we have a lot of experience with that. Partly thanks to the LED lighting, the lettuce has a high-quality texture. What’s more, we find that with light we can control even more: the red lettuce types have a more intense color with the Teens. And that’s also an important quality for producing with the market in mind.”