To paraphrase Keith Richards, I’m a pyro, not an arsonist… I love having a roaring fire during the winter – and it’s been especially enjoyable this winter. So my quandary after all those fires… What to do with Woodash…
Here are a few wood ash a.k.a. potash facts: One cord of wood (that’s a 4x4x8 pile stacked) produces about 25 lbs. of ash. Hard woods (oak, ash, maple, walnut) produce more ash with better nutrient quality than softwoods (pine, spruce, cedar, yew). The first patent taken out in the U.S. was for the refinement of potash. Pre-revolution, we exported massive quantities of potash to Britain, it was essentially our first chemical export. The potassium (that’s the K in NPK when you read the fertilizer bag) carbonate that is left behind after your wood has burned is what helps regulate the water balance in your plants. Additional nutrients in ash are calcium, magnesium, iron, phosphorous, manganese, zinc, boron and chromium. All great stuff, and your plants need them so they can reach their peak. Wood ash ‘sweetens’ the soil, which means it changes the pH. Click here if you don’t have a clue what that means.
So now that you know a bit of trivia, what’s a gardener to do with all that ash? Spread the nutrients around, that’s what. I’d suggest a soil test before getting too crazy, but generally you can use small quantities without worry, and if you’re using it with abandon, please check that you have acidic soil, otherwise you can do more harm than good. Nutrients in soil are readily available to plants when the soil is a bit acidic. Too sweet and they can’t absorb them easily. I live in the northeastern U.S. – it’s all acid. So…
*Use it on your lawn instead of those expensive bags of lime. 15 to 20 lbs. per 1000 feet is recommended. You’ll need about twice as much as standard lime.
* Use a thin layer throughout your entire vegetable garden. Be sure to till it in well. Asparagus love it, scratch it in though.
*Spread it around hardwood trees. Cherry and apple like it especially.
* You can put a cup underneath your tomatoes when you plant. Mix it well though so your litte seedling isn’t sitting on straight ash.
* Use it on your boxwood, lilac, privet, lavender and clematis. Just work it in a bit. Click here for a broader list of lime loving plants.
Keep ash away from acid loving plants like blueberries, rhodies and azaleas. Also, keep it away from potatoes. It encourages susceptibility to potato scab.
I think the best rule of thumb if you are uncertain is to do a soil test and apply sparingly.
And here is a link to a map that broadly tells you what type of soil you have depending on where you live in the world…
Thanks as always for reading EG! Happy gardening!