Should my screen gap in extreme cold weather?
In our article 'Optimising screen and vent control with lights', we explained the importance of gapping when
screens are used over supplementary lights. But during spells of extreme cold weather, is it still correct for your screen to gap — and wouldn’t a fully closed screen help to save energy?
One GrowSave member using high intensity supplementary lighting has commented that “even at minus 4 degrees C and with a 6 m/s NE wind the waste heat from the lighting still needed to be let out of the greenhouse”; so this suggests that even when it is particularly cold outside, gapping is still needed if you want to achieve your desired greenhouse temperature and humidity conditions.
However, under extreme conditions, it is best to look closely at your control strategy and make some minor modifications to your settings. This article looks at what alterations you might want to make to cope with the current spell of cold weather.
Add a second influence on screen gap?
As a word of caution, be careful when introducing a second influence. If the wrong control settings are used, it is possible for the second influence to completely override your other settings, and for the end result to be that nothing happens!
Keep a close eye on your greenhouse climate
If a period of extreme weather is short lived, you would most likely have to make subtle changes again to accommodate the prevailing conditions at the time. Giving recommendations that will work on all climate computers in all conditions is virtually impossible, so make sure that you follow these basic guidelines:
- Make sure that you understand how your make and model of climate computer applies influences and how it deals with multiple influences.
When you are using more than one influence check that your combination is delivering the response you expect (and
Remember that multiple influences are not just restricted to controlling screen gapping; they can be used for other
purposes, such as ventilation control or even minimum pipe settings.