Safety of Herbs w/Ash and Smoke

Asked September 15, 2020, 2:41 PM EDT

I live in the hills in SW Eugene and have herbs growing outside in containers. With the recent fires, they have been exposed to smoke and ash. Is it safe to use these herbs? Also, I usually dry them for winter use. Is it safe to do that? Thank you for your help.

I forgot to ask about my worm composting bin. It is outdoors. The worms seem fine. Will the compost be usable?

Lane County Oregon

4 Responses


This article should answer most of your questions:

I am adding this response below from one of the Expert's, Brooke Edmonds, quoted in the article:

First and foremost, stay safe when gardening in an area that is experiencing smoke and ash from wildfires. Avoid gardening and other outdoor activities when air quality ratings are in unsafe ranges. Wildfires produce a lot of particulate matter and large pieces of ash (gray gritty material) that can be moved long distances and be a health hazard. You can get an estimate of your area's air quality here:

Once the air quality has reached safe levels to be outdoors, then you'll want to assess your garden. Until we get our fall rains you may see a lot of ash on garden surfaces including your plants. Many folks in our urban areas may see only a thin layer of ash, but if you live closer to the wildfire or where the wind was depositing ash there may be heavier amounts. Use your best judgement and avoid creating clouds of ash that you might accidentally breath in. Don't use a leaf blower to clean plants or your garden; just a gentle spray of water from a hose will work and try to move the ash into ornamental landscaped areas like turf grass or shrubs rather than areas growing edible plants. Wear a face covering at a minimum while doing this, wash your hands afterwards, and avoid tracking ash into your house on your shoes or clothes.

Now getting to your question about safety of garden produce after a wildfire: The produce was exposed to smoke and may have ash on it. The smoke and ash won't be able to necessarily penetrate deep into the fruit or vegetable and so rinsing well should remove any residues. Rinse the produce off outside (with a hose or watering can) and then give a second or third rinse in the sink indoors. Peeling (for example removing apple or tomato skins) and removing the outer leaves of leafy greens will also reduce your risk. And wear a face covering as needed, wash your hands after handling the produce, and avoid tracking ash into your house on your shoes or clothes. Again, use your best judgement in all of this. If your garden has a heavy layer of ash, was located near a structure fire (which creates different toxins than a forest fire), or you are at all uncomfortable - when it doubt, throw it out (into the compost pile).

The University of California has a research-based publication on produce safety and wildfires that you might find useful: This publication also talks about soil testing and other things to think about before planting next year's garden. Note: this source recommends wearing an N95 mask but these are hard to find due to the current COVID-19 health situation needs.

Stay safe out there!

Thank you. I’m assuming that compost from my worm bin is safe to use since putting produce exposed to smoke and ash can be put in a compost pile. Is that right? Also, I had asked about drying herbs exposed to smoke and ash. Is that safe.

Thanks again, Liz

Your compost should be fine with the amount of ash that has fallen. Some folks (like myself) add some of the ash from our firepits and fireplaces occasionally. As long as you follow the guidelines for washing/rinse your herbs as suggested (not as ideal or as easy as doing tomatoes), drying your herbs after should not be a problem.

Thank you so much.