Don't sit back with the onions yet

Many onion fields are making a final sprint and seem, perhaps against earlier expectations, to be heading for reasonable to good yields. According to Kees Jacobs, it is now important to keep the crops healthy and to harvest at the optimal moment for a good skin quality. "You can't sit back yet."

"I mainly hear around me 'We're getting good onions after all. There's quite a bit underneath'. So the yields could well be better than expected." Kees Jacobs, onion expert at Syngenta, didn't expect it himself this spring either. But most of the signals he receives indicate that the crops have developed considerably in the past month. "Unfortunately, you can already see it in the prices, which leave much to be desired. And the onion sets were also quite good in terms of kilos; sales of those are now going badly."

With that observation in mind, Jacobs believes it is important not only to keep the onions healthy, but also to ensure a good skin quality. "Because that could become more important in sales than we have been used to in recent years."

Sap flow required for MH
The most important point of attention for the last stage of the onions is disease control, says Jacobs. "And then we are mainly talking about downy mildew. There is hardly any plot where you do not find an affected tube or spot in the crop. And because the MH has not been there that long on most plots, it is important that the crop remains vital for a while. Because MH needs a good sap flow to get into the bulb. So keep your schedule closed and only stop spraying fungicides when the necks are closed."

The advisor adds that growers should also keep an eye on other onion fungi until the end. "We have had regular rainfall recently. And leaf spot disease in particular feels good about that. And no more irrigation once the onions have been flattened. Because under that blanket of foliage a fungal climate quickly develops and bacteria can also strike."

Harvesting on time gives beautiful skin
If you want to get an onion with a nice colour and a firm skin out of storage later, it is best to harvest the onions when the foliage is about 50% green. That is quite difficult, Jacobs realises. "At a certain point you no longer know what 100% green looked like. It might be a good idea to take a photo every now and then to follow the dying." Growers often feel that they are harvesting too early when the foliage is 50% green, the advisor continues. "But you hardly gain any kilos and it is really the best for the quality. We always have to carry out our own trial harvests before the trial field manager starts harvesting. We always have nice onions when they come out of storage."

According to Jacobs, the correct method of topping and harvesting is sufficiently well-known, but occasionally he still sees that the mat of the harvester or the loader rotates too quickly or shakes too intensively. "The onion is quite a vulnerable crop, so aim for a calm product flow." The onion expert also warns about the long shafts that he has seen quite often this year. "You have to take that into account when setting the correct topping depth."

Off land or keep?
With the adjusted yield forecast, the larger area of ​​seed onions and the moderate pricing, many growers will soon be faced with the decision whether to deliver from the field or to store them. Jacobs cannot advise on this, but he does want to give growers a benchmark. "It is important to know your cost price. This is different for everyone, but one thing applies to everyone: onion cultivation has become considerably more expensive in recent years. Before corona, you were still talking about cultivation costs (including land charges) of around 1 euros. In recent years, many cultivation costs have increased, such as crop protection, energy and fertilization. I think that onion cultivation now costs around 5.000 euros. And when it comes to storage, there is a lot more to come. These kinds of calculations are crucial for a substantiated decision about your sales method."