Sam K emailed me recently about wood ash. Since I'm running a woodstove, he wanted to know what I do with the ashes.
First let me say, every location, soil, and growing situation is different. What I do may have absolutely no bearing on what you should do. What is beneficial to my garden may not be good, and may actually harm yours. Thus....you have been warned. Gosh darn, I'm down to using disclaimers! Just keep in mind that this blog is just relating my adventures of creating my homestead. It's not a how-to instructional book. Heck, if it were a book, I could be selling it. ;)
Ok, what do I do with ash. First, I run two different types of woodstoves. The one for cooking livestock feed is a TLUD (top loading updraft) stove that's primary purpose is to produce biochar. The heat is a by-product that I use to cook with. This type of stove makes very little ash, since the combustion process is limited and actually halted at the point that pyrolysis dramatically slows down.
My ash producing stove is the conventional woodstove in the house. It is a Morso stove, though the brand name has no bearing on this matter. Commercial, conventional wood burners all produce ash. The Morso makes the collection of the ash easy because it has an ash pan under the burn chamber. I run this stove briefly just about every morning and night. So each week I get two to three pans of ash.
The ash I collect comes from burning tree woods, mostly ohia, eucalyptus, and guava. These are the most common trees in my immediate area. A few other species are mixed in, when available. These include Christmasberry, mango, loquat, macadamia, citrus, ironwood, and Norfolk pine.
My number one use of ash is for adjusting soil pH and increasing potassium in my pasture soils. My soil tends to get somewhat acidic due to the fact that I am downwind from an actively erupting volcano. Our rains are acidic. The volcanic soil is calcium deficient, which doesn't help with having acidic rain.
Before applying ash, I check the soil pH. If it is 6.5 or higher, I won't apply ash. But it's always been lower since I started testing several years ago. Therefore I am comfortable with applying the ash. Oh, I test potassium too, and it has been testing low on untreated areas.
I hand spread the ash just before a rain. In the above photo I've just spread the first pan of ash. I next applied the second pan, filling in the spots that I missed or only got a light covering. That night it rained. Good.
I also use small amounts of wood ash in my vegetable gardens. The coral sand that I apply to garden soils only slowly adjusts the pH. When pH gets too low, I will use wood ash to more quickly bring the pH up to a veggie friendly level. Ash also adds potassium and essential plant minerals at the same time.
Have I seen a difference when I use wood ash? In my pastures, yes. There is a significant visual improvement. The grasses grow faster, send out more runners, are greener looking. There is less moss and less ferns. I don't know all the science behind it, but the grasses and pasture herbs seem to respond in a positive fashion to a wood ash application.
In the veggie gardens there is not as a dramatic visual change. Most likely that's because of all the other soil amendments also being used at the same time.....manures, compost, mulch, coral sand, burnt bone, biochar, urine, various nutrient teas. The garden soil has been improved as I go along, so one application of one particular amendment (such as wood ash) doesn't result in a significant change. Plus I'm not using lots and lots of ash in the garden soils. Just a bit whenever it is called for.
Do I use ash for other purposes? No. I know that wood ashes have other uses, but I haven't tried any of them. Since I have acres of pasture that need improving, I have years of use for my wood ash that I will be generating. No need to look around for other things to use it for.