Is Your Greenhouse Air Circulation Your Worst Enemy?

Your greenhouse is essential to your business, and every part of it needs to function properly. Your walls, shelves and fertilizer are carefully sourced and maintained, and your processes are rigorously implemented and constantly fine-tuned. However, there’s one part of greenhouses that may get overlooked: the air itself.

Is your greenhouse’s air circulation working for you? If it’s not, there’s a good chance it may be working against you. Here’s how to tell if the air circulation in your greenhouse is secretly your worst enemy, and what to do about it.

Warning Signs Your Greenhouse Air Circulation (Or Lack Thereof) Is Working Against You

TEMPERATURE

It’s very important to keep your greenhouse at an ideal temperature for your plants, which is between 21 to 27 C or 70 to 80 °F. If your greenhouse’s temperature is significantly higher than the air outside during hot weather, this is your first warning that you may have poor greenhouse air circulation. When your greenhouse gets steamy in the summer, this is a microclimate example of the widely known “greenhouse effect”. It is the result of heat becoming trapped inside the greenhouse by a lack of airflow, and it can have disastrous effects on your harvest. 

Conversely, in wintertime, good ventilation keeps air circulating and ensures that cold drafts are kept out, rather than freezing certain sections or plants, or lowering the entire greenhouse temperature to an unacceptable level. Regularly checking your greenhouse thermometer can help you monitor temperature changes and determine if you need to adjust anything: if you walk in and are shocked by a sweltering heat wave or a freezing chill, something is already wrong--and it may already be too late.

HUMIDITY 

Water pooling on your ceiling and walls? Excess humidity in your greenhouse is usually the product of poor ventilation. The ideal humidity for most greenhouses is 80%; more or less than this can cause problems and even put your harvest at risk.

Typically, a greenhouse will produce up to three gallons of transpirational water (essentially, water that evaporates from the stem and leaves of a plant). If this water is not dealt with through good air circulation and distribution throughout the greenhouse, it becomes a problem. Particularly in tightly packed environments where plants are close together, the water produced by the canopy can become your worst enemy as it hangs around and disrupts your entire microclimate.

A smaller and less fruitful harvest is one of the milder risks of a humid greenhouse. The most serious sign that your greenhouse is suffering from an excess of humidity is the onset of diseases.

DISEASES AND FUNGI

The final and most serious sign of poor greenhouse air circulation and ventilation is the appearance of diseases and fungal problems, both on your plants and in their soil.

Diseases in your greenhouse are the clearest and most serious sign that it needs better ventilation. Poor ventilation allows diseases not only to develop, but also to spread unchecked through your plants. 

As humid and poorly ventilated conditions lead to water becoming stagnant on plant surfaces following watering, or as a result of transpiration, this can lead to the development of mildew spores, which can be spread by irregular air circulation such as drafts. Luckily, these can also be controlled with proper, carefully planned airflow. Common problems to watch for are powdery mildew, botrytis (gray mold) and root rot. Pay attention to the appearance of downy gray mold on leaves, as well as blights, spots, discolored areas and graying stems. 

If you’re seeing any of these warning signs in your greenhouse, it may be time to reconsider how your greenhouse air circulation is configured. Contact us to learn how we can help protect and even improve your yield, and to learn more about our indoor air distribution systems.