Your heat-activated vent opener requires no external power source, just the physics of thermal expansion.
In this video, Loren explains how to set the opener and provides advice on how to protect it over the winter months.
NOTE: the screws holding the barrel are proprietary to the manufacturer and we order these in from the UK. They are not fast, cheap nor easy to replace so be careful to not lose them!
Use a trustworthy thermometer to stand inside the greenhouse and assess the temperature before setting your vents to open.
Here is a quick reference guide of optimal daytime growing temperatures of typical greenhouse crops that can guide your decisions (temperatures above or below what’s listed can lead to stunting, spindly growth or blossom drop). All of these crops prefer night time temps around 16C.:
- cucumber: 20 – 28C
- tomato: 22 – 32C
- bell pepper: 21 – 26C
- eggplant/aubergine: 26 – 32C