Dust. We see it every day. But what’s in it, and what does it do to your plants?
We’ve all heard the claims of houseplants removing toxins from indoor air, but what about the plants themselves? What does all that toxic dust do to them?
Indoor dust is generally made up of dead skin cells (dander), upholstery and carpet fibers, paper, and hair, but it also contains flame retardants, cleaning product particles, and chemicals from electronic equipment, insulation, sheet rock, paint, and flooring materials. Many of these chemicals are already known to be associated with cancer, reproductive problems, and hormone disruption in humans. They can also harm your plants.
Along with soil, animal matter, and minerals, most outdoor dust particles today also contain car fumes, plastic particles, aerosols, emissions from mining and other industrial processes, salts from eroded soils, and chemicals from nearby farms or landscapes. Wind that blows over coal-fired power plants, petroleum plants, steel mills, and mining sites carries toxic dust with it. Dust particles can also increase erosion, adding a sandpaper effect to every breeze.
In one case, the dust from California cement factories blew against nearby hillsides,
sickening or killing entire stands of California sagebrush (Artemisia californica), brittle brush (Encelia farinosa), white sage (Salvia apiana), and black sage (Salvia mellifera). These plants were critical to local birds, animals, and insects. The dust also altered the chemical makeup of the soil.
Dust as pollution
Dust is one of the most common forms of air pollution. In 2008, it was estimated that 30 million tons of dust are kicked up into the atmosphere each year. Because of urban development and global industrialization, the amount of dust in the atmosphere is increasing each year.
While 35,000 people die in car accidents each year,
it is estimated that 53,000 Americans lose their lives to car emissions
Many of these people live near freeways or other high traffic areas.
What does that say about the dust particles faced by your plants?
What does dust do to plants?
As dust falls on a leaf, the leaf is smothered. If the leaf’s surface was wet, the dust turns into a mud that collects even more dust and then dries to form a hard barrier. The amount of dust on a plant is called its dust load.
Very small dust particles can often be absorbed by plants. When this dust is simply pulverized soil or other naturally occurring materials, this isn’t a problem. Plants have evolved to handle these materials (up to a point). When this dust includes toxic chemicals, it can cause a host of other problems. Dust covered leaves also make it harder for trees to reflect sunlight, increasing the plant’s temperature. This makes them more susceptible to water stress and other negative effects of drought. Dust can have both physical and chemical effects on your plants. As dust is absorbed, it can alter cell wall exchange sites, interfering with nutrient uptake. Dust affects plants negatively in many other ways:
This means there is less energy, less water uptake, reduced gas exchange, and smaller crops. But things get worse, depending on what makes up that dust.
Pathogens cause disease. They can be bacteria, viruses, or fungi. Many pathogens blow in on the wind, and become part of your plants’ dust load. These pathogens can cause diseases such as fireblight, cankers, powdery mildew, eutypa dieback, rust, spotted tomato wilt, cucumber mosaic and many others. [Of course, Mycobacterium vaccae is also part of that dust load - these are the microorganisms that help you feel happy!]
Indoors and out, mites and mealybugs love dust. Whiteflies also have the advantage when your plants are dusty. Outdoors, mites, especially spider mites, thrive in areas with lots of dust. The dust mites in your home are a common cause of allergies and other respiratory problems. [Actually, it’s mite poop that causes the reaction…]
Reducing dust load
You can help your plants (and your family) thrive by reducing the amount of dust they have to deal with. There are several ways to reduce dust load:
Your plants and your lungs will thank you!
You can grow a surprising amount of food in your own yard. Ask me how!
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