The rule of thumb for sowing onions is usually that the crop must be sown before May 1st in the Netherlands. Last spring was a late one for most onion growers regarding when to sow onions. Most onions were sown in April, but some had to keep their patience until May. Bejo/DGS’ Onion magazine asked some growers about their experiences with onions sown in May. Is it really true that onions sown in May give 'leek'?  

Jos Keijbets  
Onion grower in Voerendaal (L)  

Jos Keijbets from Voerendaal sowed his onions on loess soil on May 4th . He normally sows in April, so sowing the onions in early May was no problem for him, he says. "Late April or early May doesn't make much difference," he says.    

According to Keijbets, conditions were not good enough to sow earlier: the soil was not yet good, or rain was predicted shortly after sowing. "We bought primed seed for the first time this year, which was a big advantage for late sowing."  The onions were up within a week, says the grower. "In the beginning, we had a dry period. Just when we wanted to start watering, each time a shower fell just in time. As a result, the onions grew nicely and we didn't have to water the crop this year."     

Sowing in May has not disappointed us this year

Jos Keijbets
Jos Keijbets

The result of the harvested onions looks good, Keijbets thinks. "Due to the late sowing, I do see the occasional 'thick-neck', but this percentage seems limited. There will probably be more tare than in other years. We estimate yields between 55-60 tonnes/ha anyway, so sowing in May has not disappointed us this year."

Marcel Kooijman  
Onion grower in Poortvliet  
 

Onion grower Marcel Kooijman sowed his two plots of onions on May 6th. Within ten days, the onions were completely on top in both plots. About a week later, there was 85-90 per cent failure on one plot. After investigation, this was found to be due to bean fly damage.  

"I then quickly decided to overseed the plot because, given the timing, I had few other options," Kooijman says. "Also, there were already hoses in the plot for drip irrigation. What also factored into the decision was that my parents had sown the onions in June in 1983 and of this they do not remember that it ended badly then."   

The over-sowing date was May 27th and within a week, all the onions were up nicely. Unfortunately, several other setbacks followed in the growing season on the plot. For instance, the plot was completely flooded once in August after a heavy downpour, says Kooijman.    

In the end, the grower is fairly positive about the harvested onions. Due to late sowing and later setbacks in the growing season, he still expects to deliver around 20 tonnes/ha net. "I had hoped for more, of course, but fortunately the yield from my other plot was a lot better," he concludes.