Now focusing on optimal cultivation conditions on onions

After a cold and wet spring, many onion fields have fallen behind. Locally, there were extreme weather conditions such as hail and dust storms. Kees Jacobs and Michiel van Mol advise on optimal cultivation conditions for the coming period.

"If you don't focus on optimal cultivation conditions now, it will be very difficult to get a successful onion cultivation." Michiel van Mol makes no bones about it. "Normally the onions have 5 to 6 pipes at the beginning of June. Now the best plots have 3 to 4. So we are well behind with the development of the haulm equipment." According to the onion expert at Syngenta, it is especially important to let the onions continue to grow without stress in the coming period. Van Mol's colleague Kees Jacobs emphasizes this. "From the longest day, the onion will concentrate on bulb formation. So we have to use the coming weeks optimally for foliage growth."

Be careful with contact materials
According to the cultivation advisors, there are 4 important points for attention for a smooth growth of the onions. First of all, the fertilization. "Don't wait any longer with the second dose," Jacobs advises, "And maybe give a little more nitrogen than you planned. The abundant precipitation in May probably led to leaching." The second point is weed control. Caution is the key word here. "The soil herbicides have worked well due to the abundant precipitation", says van Mol. "Locally even too bright, because it also caused plant loss. That is why from now on you should not tease the onions more than necessary. So be careful with the contact means and only spray against weeds that are actually there. Do an inspection round for you on the spray climbs and sprays with a coarse drop."

Trips already spotted
Unlike the onions themselves, the pest insects are not lagging behind this year. "Thrips have already been detected in onion sets", says van Mol. "So assume that the population building in the seed onions has already started. If you only half suspect that the thrips are also in your onions, you should start spraying now. Also remember that the systemic agents need a week before they are active throughout the plant." According to Jacobs, growers often still make the wrong decision when choosing means. "They think it is a shame to spray an expensive insecticide on a small crop. But that is the wrong reasoning. If you wait until there is more foliage, the thrips have already completed their first round of propagation. And then you are left behind. and the financial damage is greater." According to Jacobs, applying a lower dose is an option. "But", he warns, "then you also have to shorten the spraying interval." He also draws attention to the approaching harvest of the winter onion sets. "And at the end of June, it's time for the normal onion sets again. At those moments you have a greater chance of thrips flying into your sowing onions."

The onion and bean flies also demand attention during this period. "Some incidents have already been reported, but so far it is not that bad," says Jacobs. "The damage pattern is difficult to recognize, so the best advice is to occasionally inspect your crop with your advisor and see if you can find the insects."

Little bits of water
The last point of attention is the moisture supply. The onions are still fed up with the moisture in the top 10 centimeters at this point. In the weather forecast for the coming period, the crop will soon have a shortage again. "So have the reel ready", advises van Mol. "And if you are going to irrigate, do so little by little and with a fine drop. The crop suffers the least from this. Also on plots with drip irrigation, and there are more and more, a small application is sufficient at this stage. "

In summary, it means that the onions just need to be spoiled a bit in the coming period. "Now they are growing nicely, so hold on to that," the advisors conclude.