Bell pepper grower Geert Colbers:
"Greatest gains expected after summer solstice"
Rockwool substrate
Gubbels Nursery in Maasbree was one of the first companies to try out the special rockwool substrate back in 2015. First it was limited to six rows, then extended to a sprinkler section in 2016 and a year later to an 8 ha greenhouse. This year, 25 out of 29 total hectares of bell peppers are being grown on the slabs, to which the 7.5 cm high Plantop NG2.0 propagation blocks connect perfectly.
"Every year we see that the crop responds really well," Colbers tells account manager Frank Janssen. "The plants root quickly and grow more easily, and thanks to the slab height and the broader steer range, they start to produce fruit easier than on a lower slab." On the Supreme, the first harvest was a few days ahead of the rest and sometimes we even got extra fruit."
Faster and easier steering
Colbers thinks the greatest gain will come in the second half of the growing season. "After the summer solstice, it normally takes more effort to keep up a sufficient crop yield," he explains. "This is a lot easier on this new substrate, it's quicker and easier to steer, empties at night and is quickly saturated again in the morning." What I also like is the narrower base of this substrate compared to the GT Expert we first used. The slab is separate from the gutter edges, so water drains much faster. It may be a detail, but it does contribute to better control of the root environment."
Root development
Frank Janssen says that the effective control and the short reaction time are related to the NG2.0 fiber technology. "Our latest generation of slabs and propagation blocks has a very good capillary effect, so the extra height does not pose any problems," he says. "The water content in the substrate is very homogeneous and that translates to healthy root development. When you cut open a slab, you see that the plant uses the complete substrate volume and that there are many fine, active roots. This remains until the end of the season, so I can imagine that Geert is counting on a strong finale. Other growers have similar experiences."
Learning process
Despite the extensive experience that Colbers has gained with the Supreme, he thinks he has not maximized his yield yet. "Growing on other substrates is always a learning process of several years, so I expect that there is still some extra gains to be made. Especially since we have expanded the GroSens measuring system this year, which provides an even clearer view of the root environment and makes it possible to cultivate closer to the edge. With such healthy roots and vital plants it ought to be possible to raise the bar again slightly?"
"The roots are strong and healthy all year round, so there is hardly any plant failure," Geert Colbers (right) tells Frank Janssen. "Moreover, the plants are easier to keep generative."
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