How Does Wildfire Smoke Impact Gardens?

How Does Wildfire Smoke Impact Gardens?

“I live in northern California where we had a lot of fires and smoke. The sky was thick with smoke for quite a few days.  How will this impact my flowers?” Question from Jenna of Magalia, California

Answer: What a crazy season it has been! I have watched several of my western gardening friends struggle through the impacts of wildfires. Thankfully, many have been spared the damage caused by fire, but none are spared the ill effects of ash and smoke, which does impact plants in several ways.

Wildfire Smoke and Ash Impacts on Gardens

  1. Ash Effects: Ash can be very destructive, but it also has the potential to benefit plants. On the downside, hot ash will burn foliage. If fine and dense, it can cover foliage and keep plants from photosynthesizing as well. Rinsing it off will stop this problem. On the flipside, ash can raise soil pH, add extra minerals to the soil, and increase microbial activity and plant growth. So, it’s not all bad.
  2. Smoke Effects on Air Quality: Smoke increases carbon dioxide levels, which actually benefits plants. Plants use CO2 to convert sun to energy and release oxygen.
  3. Smoke Effects on Light Quality: Smoke lowers light levels, which can be harmful to plants growing under severe smoky conditions for extended periods of time. There is really nothing gardens can do but wait until the smoke passes.

Smoke is also drying, so be sure to irrigate your plants during these times, if you can.

I wish you the best and hope the fires stop soon. A moist, cool winter would certainly be a blessing.

Jessie Keith

Black Gold Horticulturist


Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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