Air Conditioning??

Jun 11, 2020

Cold Air
by: Jacki Cammidge, Certified Horticulturist

One of the fundamental properties of air is that warm air rises, and cold air sinks.

Why is this important?

Well, think of a hot air balloon. The air is heated with a propane heater, and pushed into the balloon envelope. Then what happens? The envelope starts to rise up in the air, making it possible to go for a thrilling balloon ride – until the air cools off, and the balloon either has to land, or needs more heat.

The reverse is what happens with air conditioning. Cool air is formed in the refrigerating unit, and it sinks to the floor. If you stand near the outlet of an air conditioner, eventually your feet will get cold.

The other aspect of this sinking or rising is that warm air holds moisture, cold air doesn’t. The combination of cold, dry air sinking down onto the top of plants on a desk, for instance, makes it instant winter, which they’re not prepared for, or evolved to handle.

So immediately, they’ll start to go into survival mode; losing leaves, showing signs of frost/cold damage, and generally be unhappy.

Place the plants in the area least likely to have the cold air sinking onto them – in the warmest window, perhaps? You may have to invest in a thermometer that can keep track of the temperature, and the humidity.

I hope you’ve enjoyed this explanation – physics is not my field of expertise, but it impacts our lives in so many ways!