Why do plants need air?

The two primary reasons plants need is air to photosynthesize (make food) and to breathe. Plants need to breathe for the same reason people and animals must breathe – they need oxygen to convert food into energy. The relationship between air and indoor plants is crucial to keeping your plants looking their best.

Air Above Ground

Air is often taken for granted as it is invisible and seems readily available to plants above ground. However, even though air is abundant in our atmosphere, there are factors that can disrupt the availability of fresh air to a plant. Stagnant air may be low on vital gases such as oxygen and high on other gases that may harm the plant.

For example, when plants are placed indoors, fresh air is depleted over time and can cause the build-up of toxic gases. A good example of this is a banana wrapped in a plastic bag. When wrapped in the bag, fresh air is depleted quickly. Oxygen levels drop and ethylene is released by the banana. The ethylene causes the banana to ripen faster than it would if it was sitting out in the open. These same types of reactions may happen to foliage plants if not exposed to fresh air, resulting in damaged or dead foliage.

Interior plants can accumulate dust, dirt, debris and other accumulates on their leaves. These accumulates can decrease gas exchange on the leaves as well as block much needed light from hitting the surface of the leaves. Keeping plant surfaces clean not only keeps them looking good aesthetically but also helps them perform better.

In some interior spaces, air movement is highly limited, causing stagnant air to build-up. The lack of fresh air may be insufficient in oxygen or other gases needed by the plant. It may also be high in gases that may harm the plant.

Air Below Ground

Air is needed for the roots primarily to allow the plants to breathe. If air is not available to the roots, it can cause the roots to fail. Root failure is a very common cause of plant stress, although often goes unnoticed because the roots are not available unless the plant is taken out of its container.

Root failure is a major problem for plants indoors. When roots fail, they cannot function properly. When this happens, roots cannot absorb sufficient water and nutrients to the plant, causing yellow or brown leaves, plant stress and a reduced life span of the plant.

Roots are denied sufficient air when the soil does not allow for air. The two main causes of this are over-watering and soil decay. Soils that are heavily saturated with water have almost no air. When this happens, the roots cannot breathe, causing root failure. When a growing medium is compacted, air pockets are squeezed out and replaced with compacted soil. Soil compaction is common with aged growing mediums. Over time most organic soils decompose and decay, causing them to compact. The compaction squeezes out air from the soil, making sufficient are to the roots unavailable.

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