Despite advances in both overhead and side screens, greenhouses have always been susceptible to having a 'cold side'. Cold air above an overhead screen will invariably collect at one gable end and this can result in a lower temperature in the growing area below the screen at the affected end. Uneven temperatures can have a serious impact both on the crop itself and on energy consumption.
A simple solution to this problem was recently installed at Springhill Nurseries, one of the UK’s foremost tomato growers.
By fitting neatly designed vertical partitions known as intermediate apex seals between the horizontal overhead screen and the greenhouse roof using LS Solarwoven material, the cold air above the screen is prevented from collecting at one gable end and therefore the temperature differential in the growing area below is reduced or eliminated. Significant temperature variations had been showing up between identical greenhouse zones despite the state of the art facilities at Springhill.
There are 2 measuring boxes in each 12,000 sq metre compartment at Springhill. Each compartment has 125 metre rows and, prior to the installation of the intermediate apex seals, the measuring boxes consistently recorded around 2 degrees variation in temperature.
More uniform temperatures straight away
The transformation in temperature distribution after installation was immediate. According to Roly Holt, who heads up the Springhill management team for the Worcestershire based family business R & L Holt, the temperatures recorded by the measuring boxes evened out as soon as the apex seals had been installed.
The improvement is even noticeable along individual rows where the uniformity along the row is remarkable compared to the previous season when parts of the row were one week behind.
Having reliable temperatures throughout the growing area should make management of the crop more straightforward and ensure even better uniformity of the final product.
Installation is straightforward in most cases, so the intermediate apex screen promises to be as a very cost effective solution to an all too common problem.