Hope all of you survived this record cold during Christmas. That was about as cold as I have been for a while.
I had an unusual question from one of my readers while at the butcher shop in Jeromesville a few years ago, which was like a question I got last week from one of my sister-in-law’s classmates. She was concerned about throwing wood ash on her garden and whether the practice of spreading wood ash on the garden was something a person should actually be doing? My reader from last week wondered whether there were any toxins in the ash or smoke that we should be aware. Since we have had some serious low temperatures, my thoughts have turned to folks who are wondering what they can do with their extra wood ash and the smoke that the wood produces.
Thirty years ago, when I was married to my first wife, we used a lot of wood in our wood stove to heat our home. It really wasn’t anything to get a coal bucket out of our stove two to three times a week. My folks would normally spread the wood ash from their fireplace on their garden faithfully. I’m not really sure that my folks experienced much improvement in their own garden from this practice.
My Amish neighbors normally spread wood ash from their cook stoves over their gardens in some way most of the year, according to one of my neighbors. The challenge is that, if there is nothing actively growing in your garden, the chance of the wood ash just going to the stream and not sticking are very high. Nutrient retention to benefit the soil this time of year is questionable at best.
Before I say anything, I believe that, if you know where you are at, you will know how to add nutrients to any garden. Therefore, test your garden’s soil and get a base point from which you can add nutrients in an intelligent fashion.
In wood ash you can normally we see potash at 10% of the volume of the ash, phosphate at 1% and trace amounts of iron, manganese, boron, copper and zinc. Some of the trace heavy metals are lead, cadmium, nickel and chromium. Phosphorous is an important component of the nutrients that plants take in for their growth, which regulates a plant’s water balance. I learned that potassium has a significant role in transporting food within the plant and creating sugars and starches. Vegetables are more susceptible to drought, frost, pest, and diseases without potassium. Wood ash or potash — not lumber waste and not coal ash — contains potassium. What is very cool about this wood ash is that a cord of wood, which is a 4- by 4- by 8-foot stack, will produce on average 25 pounds of ash. Most of it is ideal for the garden.
Here is the challenge: A cord of oak will provide enough potassium for a garden that is 60- by 70-feet, whereas a cord of Douglas fir will produce enough potassium for a 30- by 30-foot garden, and both will raise the pH of the soil slightly. Hardwoods like oak generally produce more ash and contain more nutrients — potentially three times that of softwood — and more trace nutrients than softwoods. The calcium carbonate content that is leftover in the wood ash also varies. This means that when you use the wood ash in your garden, you should not only test your soil before you start adding wood ash to your soil, but you should also test your soil after you have been adding your wood ash to your soil, at least every six months.
We go back to my initial statement that if your potassium is already high in your garden, then you shouldn’t be adding wood ash. Same goes for the pH. If you are above 7.0, you should add wood ash judiciously to your soil and not at all if above 7.5. If you have reached this point, consider helping your lawn at the rate of 10 to 15 pounds per 1,000 square feet with the same guidelines. As you may have guessed, you really want to keep your wood ash covered and protected for ease of use and no loss of nutrients because of rainwater, which can wash away the potassium.
In answer to the friend who knows by sister-in-law, I was surprised by the trees that might have poisonous smoke. These trees all deserve caution: poison sumac, edible fig trees, black cherry, Chinese laquer, camphor tree, yew and Bat’s Wing Coral tree. Don’t use normal building lumber in your fireplace because of the dangers. Black cherry has a cyanogenic compound in the bark, roots and leaves or it produces a form of cyanide. The bitter almond aroma reveals the cyanide qualities of this tree. Please take note that these toxins are minute in these trees for the most part.
Plants that like an acid environment, such as blueberries, will be harmed by adding wood ash. Wood ash does have a benefit in controlling slugs and snails when dry. As you sow carrots, wood ash sprinkled in the rows can keep the turnip fly away before you apply any water. If you sprinkle wood ash in a dry form over turnips and carrots, you can also deter turnip flies. Root crops such as parsnips, carrots and beets as well as peas and beans and fruit all do better with wood ash.
Hope you all have a great New Year. If you have any gardening problems that are indoors or out or bird issues, you can e-mail me at email@example.com. My website is ohiohealthyfoodcooperative.org. You can find links to the blogs soon.
Eric Larson of Jeromesville is a veteran landscaper and gardening enthusiast and a founding board member of the Ohio Chapter of Association of Professional Landscape Designers.