Lettuce pellets enabled mechanisation

Pelletising may sound like a simple invention, but it brought major efficiency gains to lettuce cultivation worldwide by allowing growers to mechanise sowing. Pelletising was one of many seed-quality and seed-treatment innovations throughout the decades, says Henk van Lenteren, who was responsible for quality and operations at Rijk Zwaan. “The pellet not also enabled customers to save on labour, but also accelerated quality-related improvements.”

Soaking overnight

Back in 1960, when Henk (now aged 73) was still a boy, his father – who was a representative at Rijk Zwaan – used to soak lettuce seeds in water in the cellar overnight to prepare them for sowing. “It led to better germination. He didn’t know exactly why, but it worked. Nowadays, to ensure optimum seed quality, all seeds are tested for quality, germination, health and genetic composition using state-of-the-art techniques at our Seed Quality Centre.”

Perfectly potted, one by one

Henk himself subsequently joined Rijk Zwaan, where over a period of almost five decades he was responsible for seed quality, setting up a quality system, seed treatment and complaint handling. Pelletising was a major breakthrough. The process was invented by Royal Sluis, whose pelletising department later became Incotec. Rijk Zwaan still works together with Incotec for pelletising to this day.

“Up until 1970, growers sowed in a seedbed and then transplanted the seedlings into pots. Lettuce seeds are elongated, so mechanisation was not possible – but pelletising them into a round shape changed that. A machine could perfectly place each pellet into a pot, one by one. This created huge labour savings for growers. Slowly but surely, plant raisers adopted this specialised process.”

Priming overcame seed dormancy

In the 1980s, pelletising also accelerated other seed treatments. Since the seedlings were no longer being transplanted, seed quality became much more important. “Needless to say, plant raisers wanted each and every pellet to grow into a seedling. That’s how priming came about. This technique enabled us to overcome a seed’s dormancy just before the emergence of the first root. That was a huge step forward. Other new techniques included thermal treatment, which raised the temperature at which seeds would still germinate. That was necessary because our seeds were also being sold to growers in warmer countries such as France,” Henk explains.

Complaints improved quality

These new treatments were often solutions to problems that growers or plant raisers encountered in practice. If seed quality was disappointing, they let Rijk Zwaan know. It was no coincidence that complaint handling was also part of Henk’s job. “If we received a complaint from a customer, I made it my priority to talk to the customer and also my colleagues to get to the root of the problem and find out whether it was our fault. If it was, we not only compensated the customer but also developed a test to prevent the problem from happening again. This meant that our customers could depend on continuously improved seed quality and delivery reliability.”

Advanced techniques at the Seed Quality Centre

Henk is in no doubt that Rijk Zwaan will continue to further improve quality and reliability in the future: “When I see all the advanced techniques used at the Seed Quality Centre and all the smart people working at our company, I have every confidence in that. I expect AI will increasingly play a role in this as well. And customers can definitely count on our commitment.”