Albert Thunnissen about Grodan Vital

"The NG 2.0 has better drain and steering properties"

Solyco has used Grodan Vital stone wool slabs to grow tomatoes for years. According to manager Albert Thunnissen these slabs are the perfect match with the unusual drip irrigation system at the nursery. “The new generation, Vital NG 2.0, suits us even better. The water content drops faster and the slab quickly resaturates. That increases the steerability of the crops.”

Solyco produces large beef tomatoes, large round tomatoes and plum tomatoes on three sites in the municipality of Lansingerland. The three sites cover a total of 17 hectares, a considerable proportion of which is equipped with grow lights. Albert Thunnissen grows Merlice and Ducovery under artificial light on the six-hectare site in Bleiswijk. The current crop was started on 17 October last year with grafted, topped plants with three stems.

Going our own way

“I don’t know of any other growers who do that, but it’s a system we’re very happy with”, says Thunnissen. “We are used to going our own way and being different to the rest doesn’t bother us”, he says. “That ‘dare to be different ‘attitude is reflected in our choice of substrate. Over the years we have tried a whole variety of slabs, but our favourite is Grodan Vital. That makes us an exception in the world of tomatoes, but the slab perfectly suits our drip irrigation system. We use 2-litre drippers instead of the more usual 3-litre ones. With a modest capacity of 33 cc a minute it’s a challenge to create drain on most slabs as the water spreads over the entire slab too easily. But Vital has a relatively vertical structure. That has two advantages in our situation: it’s easier to create the necessary drain and easier to dry the slab if necessary. I can just leave the slab and let the water content gradually reduce to 55-60%.”

The new generation of slabs - Vital NG 2.0 - makes the manager at Solyco even happier. “It drains faster and restauration is faster too”, Thunnissen explains. “That increases the steering range of the crops. In my experience, the 2.0 is marginally moister than the old version at the end of the day if a standard irrigation programme is used. I have adapted the irrigation pattern accordingly so that smaller volumes of water are given in the late afternoon.”

Faster drain and restauration

It drains faster and restauration is faster too

Albert Thunnissen

Stay alert

“Our cultivation system is pretty basic”, he summarises. “We don’t used any advanced measuring sensors, but use the traditional system with a scale, drain meter and EC meter. That keeps the costs down, but you have to stay alert. I walk around the greenhouses a lot and cut open four or five slabs every day to get a sense of how well the roots are growing and if the water management is right. These two aspects are better than ever on the new slabs. I regularly adjust the irrigation times to adapt the watering strategy as well as possible to the light levels. We also keep our crops active by stimulating transpiration.”

Grodan’s Next Generation 2.0 technology increases the water retention capacity of stone wool slabs and blocks, resulting in superior water management and greater crop steerability. NG2.0 was introduced some years ago in a limited range of innovative products but has been incorporated into the entire range since then. From summer 2018, NG2.0 is the new standard for all Grodan stone wool slabs and blocks worldwide.

NG2.0 incorporated in the entire range worldwide


vegetable solutions, substrate slabs, vegetable, growing, tomato, Greenhouse vegetable production, grodan