Air Circulation for Plants

Why is Good Air Flow Important for Healthy Plants?

Good Air Circulation in the Garden
© Frédéric Collin / Getty Images

Good air circulation is an overlooked necessity for a healthy garden. Providing airflow around your plants is as important as sunshine, water, and organic matter. You may think that plants sitting out in the open would get plenty of air, but that's not always the case. Indoor plants can fare even worse.

Why is Air Circulation Important for Plants?

When airflow around and through a plant is impeded, your garden can remain damp for long periods.

And dampness is the perfect condition for the development of many fungal diseases, like powdery mildew and blackspot on roses. To make matters worse, water on plant leaves helps to transmit spores and other problems from one plant to another.

It's not just wet leaves that cause problems. Damp soil is also a big draw for many insects, like slugs and fungus gnats. They will nestle in and make a home for themselves while feeding on your plants.

Dampness is much less of a problem when air can flow through and around your plants,  A gentle breeze is all that is needed for this benefit. A strong breeze will even minimize damage from flying insects since they won't be able to settle on plants for long. Even pesky mosquitoes and gnats have a hard time annoying you, on a windy day.

Also, many plants need to bend and sway in the wind, in order to strengthen their growing limbs. That's why it is no longer recommended that young trees be staked.

How to Provide Good Air Circulation in the Garden

Air needs to be able to flow through the plants. If the leaves of your plants are not swaying with a slight breeze, your garden is not getting good air circulation.

Many sources say to adhere to the recommended spacing between plants, but few of us are willing to do that.

We want the look of abundance. You can still have a full border, but you need to choose your site well.

  • Make sure it has plenty of sun exposure, especially in the morning, when dew is settling in. Be particularly vigilant with plants that are mildew magnets, like phlox, bee balm, and lilacs.
  • Nearby walls, hedges and other tall structures should be taken into account when laying out your garden. These will not only block light, they also cut off breezes. Make sure there is plenty of room between these structures and your plants.

Special Considerations for Indoor Plants

Houseplants and plants in greenhouses or under lights will need air flow even more than outdoor plants. If your plants are near a window, they may get all the circulation they need. Even if the window is kept closed, the fluctuation in temperature will cause a slight breeze.

However, your best bet is to use a fan. It does not need to blow directly on the plants, as long as it causes the air to circulate throughout the room. This will not only prevent dampness, it will also prevent cold and hot spots and condensation.