Attention to clean glass rewarded with gain in light
In vegetable production the old rule of thumb still applies: 1% more light = 1% more yield. For this reason, dirty glass is not desirable.
In the mid 1980s a modern greenhouse had a total light transmission of 70%. These days that figure is over 80%. Over the years a lot has been done to ensure that the crop receives more light: Larger glass panes; fewer reflective parts; narrower construction parts; and coatings on glass. A vulnerable part however is the glass itself. This becomes dirty over time, both on the inside and the outside. All kinds of things can cause this: Algae; desert sand; dust; soot; and deposits of volatile crop protection products. The result is a few per cent loss of light. In exceptional cases this can rise even further. This is the case, for example, when the infamous Sahara sand travels thousands of kilometres by air and covers us all in a layer of dust.
Shelter for diseases
Loss of light is not only annoying – after all it costs yield – the layer of dirt also forms a shelter and breeding ground for pathogens. The outside can be kept clean by using a greenhouse roof washer. However, that is not so for the inside. If a crop is present in the greenhouse the cleaning products may harm it. Therefore, for vegetable crops, the change-over of the crop is the preferred moment to deal with the dirty glass.
Safe to use
For this purpose Mardenkro offers the glass cleaner, GS-4 Xtra. The product works without brushes; simply spray on the right concentration and then rinse off afterwards to ensure the effective removal of all the dirt. All glass cleaners contain fluoride; however, when using GS-4 no gaseous hydrogen fluoride is released because the product is based on ammonium bifluoride. Therefore it is safer to use. It also results in less roughening on the glass than when using other products.
Cleaning greenhouses with fluoride based agents
The horticultural sector often uses a cleaning agent based on fluoride to clean glass. Fluoride chemically cleans the surface of the glass. Several minutes after application the treated glass along with the dirt is rinsed off. But this principle should not be applied to synthetic greenhouse roof coverings.
Getting more light into the greenhouse in three steps
An old growers saying has it that 1% more light yields 1% higher production. Scientists have since shown that this is in fact a bit more nuanced: depending on the crop this varies from 0.5% to 1.25%. However, the principle remains the same; during a large part of the year all of the sunlight can effectively...