Is the Smoke Bad for My Plants?

If trees are the lungs of the Earth, then it’s reasonable to wonder how the plants of the Northeastern United States are faring during this week’s record-breaking wildfire smoke event. Certainly, we oxygen-gulping inhabitants of their sister kingdom, Animalia, have seen better days: Wildfire smoke contains tiny particles known as PM_2.5 that penetrate deep into our lungs, enter our bloodstreams, and cause irritation and inflammation while exacerbating life-threatening conditions and doing who-knows-what-else. For living beings with the evolutionary luxury of both bipedal mobility and frontal cortexes capable of inventing the air purifier, it is wise, if at all possible, to get out of the smoke and stay out.

Meanwhile, trees, home gardens, and the precious Finger Lakes vineyards had to stand and bear an Air Quality Index that topped 400 in places. So … are the plants okay?

First things first: Is the wine safe?!

Maybe you’ve heard of “smoke taint,” an effect that happens when the highly permeable skin of a grape absorbs wildfire smoke, causing the resulting wine to taste “sooty and dead.” Smoke taint has been a serious problem for vignerons in Washington and California as wildfire seasons have gotten worse. The good news is, in this particular case, it’s still early enough in the growing season that New York’s wine industry — the third largest in the nation — likely dodged a bullet.

“Even if it’s a fairly severe [smoke] exposure, the real risk starts after the bloom is finished and the berries start to form,” Dr. Tom Collins, an assistant professor of wine and grape chemistry at Washington State University, told me. “So if you have smoke events that occur after that time, then the risk goes up significantly.” But since New York grapevines are still pre-bloom, “they probably are not going to be hurt by this.”

Kyle Anne Pallischeck, the executive director of the Finger Lakes Wine Association, confirmed that “from conversations I’ve had, there isn’t much concern at this point” about the Canadian smoke impacting the season’s harvest. Phew.

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Is smoke bad for my garden?

Smoke is made up of carbon monoxide, carbon dioxide, and particulate matter, the latter of which wreaks havoc on animal respiratory systems — which plants luckily don’t have. More importantly, plants use carbon dioxide for photosynthesis and there’s some evidence that suggests wildfire smoke as a result might increase plant productivity.

Additionally, the same researchers found that smoke potentially allows plants to use sunlight more efficiently since the smoke diffuses light: “Whereas direct sunlight might fall mainly on upper foliage, leaving the rest of a plant in shade, diffuse light can reach a greater number of photosynthesizing leaves throughout the vegetation canopy,” Eos explains. (Other research indicates photosynthesis might drop because of reduced light intensity, though this likely only matters if it happens for a prolonged period of time in the window where a crop is ripening).

Smoke, however, is much worse for plants when it’s from a nearby source since the ash can clog stomatal pores, effectively choking the plant. But while the smoke event in the East still “looks awful [and] it still smells awful, it’s not going to have as big an impact on local agriculture,” Collins said, because the fires are hundreds of miles away. By the time the smoke reaches most of the U.S., “a lot of the things that are most problematic to plants have begun to fall out or are reacted in the atmosphere into things that are less impactful.”

Is it safe to eat produce from plants that were outside during the smoke event?

You worked hard to cultivate your dramatic little strawberry plant and you should get to enjoy your harvest, darn it! But maybe watching the plant endure all that yellow air has ruined your appetite.

You don’t have to hold back, though. Smoke likely won’t have penetrated deep into the plant and washing it off well is probably the biggest precaution you’ll need to take before you enjoy it. Of course, use your best judgment: If your plant is covered in a fine layer of ash, you don’t want to put it in your mouth (“When it doubt, throw it out,” the Oregon State University concurs).

You can also be extra safe by soaking fruits and veggies in a white vinegar solution at a ratio of one teaspoon of vinegar to three cups of water.

Should I be taking care of my garden right now?

Farm workers are one of the highest-risk groups for short- and long-term health effects from wildfires due to their strenuous outdoor labor that can’t often be put off. But if you have the ability to opt out of tending to your garden for a few days when the AQI is this bad, then yes, absolutely opt out.

Read more about the wildfire smoke engulfing the eastern United States:

Why Are the Canadian Wildfires So Bad This Year?

How to Stay Safe from Wildfire Smoke Indoors

Wildfire Smoke Is a Wheezy Throwback for New York City

Wednesday Was the Worst Day for Wildfire Pollution in U.S. History