Consultancy

Longer roses under ReduFlex Blue

When it becomes very warm roses quickly tend to remain too short. Nice2Get! now has three seasons of experience with ReduFlex Blue. “We clearly see more stem elongation,” says owner Robert Koot.

Visitors to this year’s Keukenhof, Holland’s famous outdoor flower show, chose Harlequin by Nice2Get! as the most beautiful rose of the year. Some 30,000 people voted for the rose via computer. It was a clear indication that the bi-coloured rose (red and white) is very popular.

However, it is not an easy variety to grow, says Robert Koot. “It can’t withstand a lot of heat or light and stem length lags behind in the summer. If you don’t use a coating you stand to lose a lot. Since we started using ReduFlex Blue we see considerably longer stems.” 

Determined by blue/red ratio 
The stem length is an important quality characteristic of roses and other cut flowers. It is known that the ratio between blue and red light partly determines the elongation in the crop. Knowing this Mardenkro developed ReduFlex Blue. The coating allows less blue light to penetrate and hence results in more stretching. In addition, it reflects an important part of the infrared, keeping the greenhouse temperature lower. Nice2Get! grows five varieties of roses in 7.5 hectares of glasshouses in Nieuwveen, the Netherlands. The company pays a lot of attention to quality and grows according to the environmental certificates MPS-A and MPS Socially Qualified, indicating that they meet high requirements in terms of environment, safety and health. 

More stretching
“In the past we didn’t use a coating but instead used a screen,” explains Koot. “This leads to a crop with chlorosis and shorter stems. This improved a lot when we started using ReduHeat.” Based on advice from a crop consultant two years ago we decided to try ReduFlex Blue. We are now in the third season and we notice that this coating allows in more light and indeed leads to more stem elongation.”

Due to the higher PAR-light level, compared with using the screen, the crop can optimally produce assimilates. Koot notices that the heat reflection property reduces greenhouse temperature and produces a more vigorous crop, which clearly produces longer stems. He doesn’t know exactly how much difference it makes to the length because all the greenhouses are now coated with ReduFlex Blue.

Promises fulfilled
Compared with ReduHeat the number of hours that the screen has to be used is the same. Compared with the old situation - without a coating - the number of hours when screens are needed has dropped substantially. “I like this coating; it does what it promises. Also, it stays on well; it was just as thick at the end of the season as at the beginning and it was easy to clean afterwards,” says Koot. Due to the cool summer he decided to remove the coating in week 33. Right after the roses had to deal with an unexpected heat wave so the screens had to be used a lot. “You learn the hard way. The weather is much less predictable which makes it more difficult to choose the right moment to remove the coating,” he states.

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