Strong roots and stable transpiration keep pepper plants resilient

Whether it is due to new, more aggressive fungi, a structurally high plant load, or suboptimal climate conditions, the fact is that many pepper growers have had significant damage to their crops in recent years, caused by root problems that had not affected them in the past. Research conducted on the phenomenon has so far not yielded any concrete new insights. 

Roots make the plant

“You can come up with various explanations for the sudden increase in root problems. They may all have an impact and cause plants to be exposed to stress, which increases the likelihood of fungal infections. You can also turn the story around and make sure the plant is more resilient to stressful situations. Plants with strong roots from the outset and that are not overstressed, have no reason to get sick and drop out prematurely.”

With these words, Ary de Jong of HortiTech outlines the starting points of a trial supported by Priva. In this trial, the aim is to achieve a resilient pepper cultivation on rock wool, based on steady growth and balanced control using Plantonomy. 

Windows open and close gradually

Plants with strong, finely branched roots can benefit you throughout the entire cultivation process. Especially when the crop needs more moisture and nutrients for transpiration, growth and fruit development. “When you manage the plant’s activity and adjust irrigation to the plant's water uptake (transpiration/absorption), the roots remain healthy and the plant performs better,” says De Jong. “Then it’s no problem at all if the temperature is a degree cooler than you might want for a given light sum”

The experienced grower emphasizes the importance of opening and closing windows and screens gradually. That way you avoid abrupt changes in the moisture balance of the greenhouse and crop. This gives the plant time to adjust its water uptake and transpiration to the changing conditions. The result is a crop with excellent yields, which still has healthy and vigorous growth late in the season, even in the slab. “Pepper growers who visit are always impressed by what we have achieved here so far,” says a satisfied De Jong. 

Never a root problem

This gradation is not usually built into conventional controls. However, modern, data-driven instruments like Plantonomy do provide it. That is also the experience of Antoni de Bruin from Klazienaveen. He grows the yellow pepper variety Levente in two greenhouses, each covering 3 hectares, and is also active as a cultivation adviser.

“I’ve been working with Plantonomy in one greenhouse for two years now. I really like it,” he says. “I’ve never had any root problems here, maybe because I've always paid close attention to the roots and watering, and I do my best to avoid crop stress.”

De Bruin finds this to be more important than ever. “Modern varieties can produce an awful lot, but that also demands a lot from the roots. If they can’t deliver what the plant needs above ground, the plant gets out of balance and things can quickly go wrong. Both above ground and in the slab.”

Better results

In his first year using Plantonomy, De Bruin – then still cultivating on rock wool – managed to achieve record production with a crop that remained in good condition right up to the end of the growth cycle. This year he switched to an organic substrate. “This makes it even easier to achieve a healthy, finely branched root system. I see that as a prerequisite for continuing to achieve high production levels. In the other greenhouse, I still manage cultivation the traditional way with Priva Connext. That’s a conscious choice, because now I can compare them and see what’s working and what isn’t.”

Stable transpiration

De Bruin expects to be using the new steering method in his other greenhouse in a few years. "It delivers better results structurally," he summarizes. “And like Ary in the Westland region, I don’t worry about one or two degrees of deviation from the ideal. Stable transpiration is what’s more important to me, and the program automatically corrects the temperature. I can almost have blind faith in that.”

He emphasizes this by noting that his current crop is performing even better than last year’s. This is despite planting later (February) because of a small greenhouse renovation. I’m surprised by that myself, because I'm putting less rather than more time into cultivation compared to last year. This tells you that the control settings are well-tuned towards the crop’s potentials as well as its limitations.”