"Sometimes you have to take meticulous measures without hesitation," says Chris Noordam with TopKrop, a trade nursery in leafy crops. 'Rigorous measures' sounds more serious than it is, but you can still call chalking in February at least a striking decision.
"After a dark winter, the crop always needs a little bit of time to get used to abundant daylight. Leafy crops can handle this, but you want to exclude all risks. Too much light might be beneficial, but one minute of lack of moisture can cause quality problems a few days later. Now we can harvest peacefully without worrying about the quality."
Unlike previous years, Chris did not apply the chalk himself this year. A conscious choice. "Just to see once again the advantages and disadvantages of both ways of chalking. This enables you to gain experience for the future. The advantage of doing your own chalking is that you can determine exactly where, when and how much chalk you apply.
If you have it done, you have to fine-tune it a bit more. The advantage is that it goes faster and that was in particular very welcome this year. Now we were ahead of the great demand for chalk and also, it was excellent chalk weather: no wind, and temperatures above 15 degrees Celsius."
Determine timing of harvest better
It is hard to imagine that in the past, growers of leafy crops in the greenhouse, such as Chris, could manage without chalk the summer. "Yet that was true. It was much more cloudy in July and August and that's been missing much more in recent years. Clouds that are welcome, because certainly leafy crops also need their moments to cool down."
Once the chalk is on the greenhouse roof - and remains there because it is not economically feasible to remove chalk and later to re-apply it again during the season, according to Chris, the various leafy crops including heads of lettuce and Lollo Rossa can just continue to grow. "Now we can determine the harvest moment even better and have it linked to our sales planning. After all, the peak periods between April and September are now getting closer."