Helping plants breathe in winter

 

Carbon dioxide, or CO₂, is one of the main elements required by plants for photosynthesis. But plants in greenhouses can quickly run out of CO₂ if outside air is not allowed in. So when the winter sun shines and plants become active, they may not grow at all.

Ben Geijtenbeek, Senior Crop Technical Specialist at Syngenta Flowers, based at Enkhuizen in the Netherlands, describes a lack of CO₂ as “the hidden enemy”.

He says, “In general, there is sufficient CO₂ in the air. But in winter, because of the temperature, sometimes greenhouses are kept closed. The CO₂ is used up and the assimilation process, or photosynthesis, is delayed or blocked completely because there is no exchange with the outdoor air to reload the greenhouse with CO₂.”

Ben says this can become worse on sunny days when greenhouse plants become more active and require more CO₂.

“Because we cannot see or smell a shortage of CO₂, it is a hidden enemy, which can easily block growth. A chain is only as strong as its weakest link.”

To avoid a lack of CO₂, his advice is to always ensure the greenhouse is ventilated to reload it with this important element, especially on warm and sunny days.

“The windows need to be opened a few centimetres regularly or, when it is freezing outside, maybe the door can be opened a little, at least a few times a day for half an hour.”

This simple tip will prevent growth from being blocked and help maintain plant quality even in less favourable conditions.