Tips on Taking Care of Garden Plants After Smoke and Ash Exposure

The smoke emanating from numerous Canadian wildfires has reportedly caused a significant drop in air quality across large swathes of the Eastern part of the United States.

Many Western states already experience this problem frequently. As a resident in the New York City suburbs, the air quality around me became smoky and orange, an issue that was temporarily classified as “hazardous” by monitoring agencies.

When the air quality was at its worst, I took precautions such as wearing a mask indoors and keeping my dog primarily inside.

Unfortunately, my plants were left out in the garden with no means of protection from the poisonous air, and had to inhale the harmful particles through their small pores in the leaves.

In the event that your area has been severely impacted by smoke or ash, it is imperative that you prioritize the safety of yourself, your home, and your pets. However, once you’ve ensured their well-being, it’s essential to take steps to help your plants recover from the exposure as well.

Oregon State University Extension community horticulturist and plant pathologist, Brooke Edmunds notes that plants can typically rebound if they’re only exposed to smoke particles for brief periods. However, if the exposure is prolonged or there’s a heavy amount of smoke, the situation is entirely different.

Edmunds added that the impact of smoke and ash on your plants is dependent on how close the fires are and how long the exposure lasts. She also noted that there could be a localized effect, where one garden might be inundated with ash, and another half-mile away might not see any ash fallout due to the way the wind moved the smoke and ashes.

The pollutants and small particles settling on your plants can obstruct the sunlight which is crucial for photosynthesis. Photosynthesis provides energy to the plants, and reduced photosynthesis indicates reduced energy levels. Consequently, weaker plants may demonstrate slow growth and diminished vigor.

Moreover, the volatile organic compounds present in smoke can have a lasting impact on the leaves and other parts of the plant, disrupting their nutrient intake capabilities with prolonged exposure. Although the damage may not be noticeable immediately.

Edmunds recommends that homeowners should keep an eye on their plants for the remainder of the season and ensure they receive the necessary care and attention because such events may cause additional stress on plants. She added that with appropriate care, most plants will recover from the exposure.

It is advisable to wash plants to remove any residual smoke particles using a gentle spray from a hose, following which you can provide them with an adequate amount of water to rehydrate them. Wait until the air clears and the plants have fully recovered before fertilizing them again.

In the instance of ash fallout, Edmunds advises against employing leaf blowers to eliminate them, as it can increase the risk of inhalation. She emphasizes the need to prioritize your safety as a gardener always.

The accumulation of ash particles can adversely impact soil chemistry, altering pH levels, and decreasing nutrient availability for specific plants, notably those that require acidic soil conditions.

If you detect more than a light dusting of ash deposits in your garden after a wildfire, it is advisable to collect a soil sample and seek guidance from your local extension service for testing and advice.

If you reside in an area that is susceptible to wildfires, it’s wise to plant less vulnerable species that can better withstand future exposures. Native plants tend to be more resilient than exotic species. For recommendations regarding suitable plants for your area, obtain guidance from your extension service, botanical garden, or horticultural society.

Edmunds explains that individuals are often concerned about the safety of edible plants after exposure to smoke, but smoke cannot infiltrate the produce. However, if there is a visible layer of ash present on the fruits or vegetables, Edmunds suggests rinsing them using a solution of 1 part vinegar and 9 parts water or peeling them.

Edmunds adds that as it is still early in the season, one probably won’t run into any problems with their produce.