Gardening Column

I have had a number of calls about the impact of ash moved from the regions’ wildfires onto both native and cultivated plants.

In general, the ash itself won’t hurt the plants. But ash deposited on ripe strawberries is hard to remove. We learned that when one Mt. St. Helens ash plume blew into Columbia County about two weeks after the big eruption. At the time, we had over 800 acres of strawberries here and it was clear, this ash was very difficult to remove from a strawberry or late season raspberry or blackberry.

For a home gardener, brushing the berries lightly with a soft toothbrush worked (and still works) but that didn’t make it for a commercial grower. There were significant losses. A few other plants like spinach which has an odd type of leaf surface that captures stuff and some lettuces may be harder to clean than normal. But otherwise, there aren’t any precautions about eating them. The only exception would be if your garden was near a house or commercial facility that burned. There could be toxic components to that ash-laden smoke. But, as of this writing, we haven’t experienced the close-up fires.

The wind event just before the fires started in other parts of the state also did less damage here than I feared. With soils very dry, tree toppling was scattered and modest. Highly exposed deciduous trees may have lost leaves but that isn’t of much consequence either. I am watching to see if there will be any impact from the dark days from the smoke swirling around us. It didn’t help our moods. But I am wondering whether it might trigger earlier dormancy in our deciduous trees and shrubs.

Their leaves respond to the normal increasing length of the night to initiate shutting down for winter. Will they be tricked by this event with day mimicking twilight? It may not be easy to tell unless you had kept good records of time of leaf drop in certain trees. But I couldn’t find much in the literature about the impact of this kind of dramatic lowering of the light intensity on their growth and function.

Tomato late blight

As this is being written, it appears we will be going into a cooler and rainier cycle. Up to this point, it has been a very good tomato year. But one disease that makes our tomatoes miserable is tomato late blight, a fungus that thrives in cool, moist conditions. If there are good sun breaks between rain showers, the disease can’t really get going. But if we have several days of back to back to back mistiness, watch out.

You might consider getting some copper based fungicide (many forms considered “organic”) and apply it before a rainy weather pattern develops. It won’t save all your tomatoes but enough so that if it warms back up, your harvest will continue. This is the same disease that caused the Irish potato famine in the mid-1840s. There is little or no resistance to this disease in most tomato and potato varieties.

Spices and herbs are good for you

Cornell University scientists have found that onion, garlic, allspice, and oregano all contain powerful bacteria-fighting compounds. These were the strongest of all the seasonings tried, killing all 30 micro-organisms that they were tested against. Included in the test were Salmonella and E. coli. Chili and hot peppers were moderately effective. There are indications that spices used in combination might be even more effective than their use individually. Bring on the curries, harissa, and the wonderful Mexican molés.

Bats about to take off

After putting on layer of fat for the winter, our little brown bats are about to make their trek to their hibernation grounds. It is not really clear where all our bats go. In the Coast Range (Mist and Vernonia), they simply disappear. In the southern end of Columbia County, there is good evidence that they migrate to caves in the Cascades. There they huddle together in one large semi-squirmy mass. If the wind and cold start to penetrate the cave, they can increase their metabolism to generate more heat. I am told that they get up every two weeks to see if winter is over.

Those of you who found that bats had made your house their home will soon have the chance to patch the cracks and crevices that gave them access. Bats can get into holes about one quarter of an inch in height. If you have an older house, I think you and the bats will stay very close friends. Those houses are almost impossible to tighten. Newer houses can be caulked and screened to reduce entry points. The bats will be gone by mid-November and generally don’t return until March.

Pressure Gauge Testing: Free at the Extension office in St. Helens. Contact for questions and requests for accessibility-related accommodations: by phone (leave a message for Jenny Rudolph) 503-397-3462 or by email at

COVID restrictions are still in place at our office which is located at 505 N. Columbia River Highway, St. Helens, OR 97051.

Free newsletter

The Oregon State University Extension office in Columbia County publishes a monthly newsletter on gardening and farming topics (called County Living) written/edited by yours truly. All you need to do is ask for it and it will be mailed or emailed to you. Call (503) 397-3462 to be put on the list. Alternatively, you can find it on the web at and click on newsletters.

Many Extension publications available online

Are you putting up salsa, saving seeds, or thinking about planting grapes? OSU has a large number of its publications available for free download. Just go to Click on publications and start exploring.

The Extension Service offers its programs and materials equally to all people.

Contact information for the Extension office

Oregon State University Extension Service – Columbia County


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