Don't Throw Away Those Wood Ashes! - Part 1 - Soil Treatment

If you live in the Northern part of the US like I do, then you may be a prodigious burner of wood during the winter. Wood is a great fuel source for several reasons:  

    1. It's inexpensive in comparison to electric heat as an example.
    2. It's much better for the environment than burning fossil fuel oil.
    3. The left over wood ash is a valuable resource as it has several practical uses.

I wanted to go over just one particular use for wood ashes at this time, which is for the organic gardeners and the bio-dynamic gardeners among us. This use is the application of wood ash to garden soil, as an alternative to using store bought bags of lime. BTW, this is something that I actually do, not just something that I thought would be nice to write about. Also, before we get started, let’s first mention that a level of common sense needs to enter the picture. I am going with the assumption that you are burning good clean wood and starting the fire with clean newspaper and/or clean cardboard.

Anything that is questionable, that you should not be burning, like plywood, pressure treated wood, painted wood, plastic, antelope carcasses, spaceship materials or plutonium would probably lessen the value of the wood ash. Therefore, we are going to make the assumption that you are fist of all burning responsibly.

Using Wood Ash on the Garden

We'll be discussing how you can use wood ash as opposed to lime in the next few sections. There is an awful lot of information online about this subject. You can get very specific details about how much of each mineral is in a typical pound of wood ash, etc.

It bears mentioning that while these statistics are readily available, all wood ashes are not equal. Hard woods and soft woods are very different. Also, local growing environments and conditions all affect the numbers. The bottom line however is that the wood contains pretty much everything that the tree needed to stay alive. The wood is an abundant source of minerals and even other plant foods, even after burning. The wood ash is a very high source of calcium. Wood ash is about a quarter calcium.

Why Use Wood Ash or Lime to Begin With?

Ancient cultures always used their wood ash from cooking as a soil additive. Think about it, what else could they do with it, make sheet rock? Many modern cultures still do this ceremoniously. But why did they do this? What were the scientific reasons?

You might think it was because they didn't have Miracle Grow. Well, they didn't but that isn't why. There are several reason, but here are the top two:

• Alkalinity
• Calcium

Let's first discuss alkalinity. You might be wondering:

Why must you raise the alkalinity, don't some plants like acidity?

Yes, many plants prefer a range of pH that is slightly more acidic than neutral. Also, plants differ as to their individual pH range requirements, but generally a slightly acidic soil pH will be enjoyed by your plants. That being said, rainwater causes some pH issues in garden soil. Unpolluted rainwater has a typical pH value of about 5.6, which is a result of something called carbonic acid. Since rain falls repeatedly the soil is being regularly acidified. If the rainwater is polluted the pH could even be much lower, to almost dangerous levels. Therefore, you may need to periodically add some form of 'liming' agent, like wood ash. Think of it as regular maintenance.

Since the soil in every gardening area can vary, you may decide to test your soil pH. that will let you know exactly where you are and then you can make the determination on whether or not to 'lime'. Most gardeners do some form of 'liming' every second or third year. It depends what the situation calls for. The next item is Calcium. You hear all kinds of wisdom about Potassium, Phosphorous and Nitrogen, but not nearly as much as Calcium. Why would your plants need Calcium? There are a few main reasons:

• cell wall development
• root and shoot growth
• proper enzyme activity
• proper metabolism
• nitrate uptake (nitrate is a usable form of nitrogen)
• physical strength in order to avoid pathogen attacks to cell walls

With all of those important reasons, it makes you wonder why there aren't the big four plant nutrients.

The best part is that wood ash is generally both readily available and inexpensive (free) if you are in the habit of burning wood throughout the winter months. Therefore, 'liming' your fields with wood ash is cost effective, biologically sound and a true expression of sustainable agriculture.

How To Do It

As you get the ashes, simply spread them out over your designated garden area. You do not need very much to make a valuable impact. You can even toss it out onto the snow if the ground is covered.

Also, always remember, never apply hot coals to the ground. Always make sure that the ashes have completely burnt out first.

In Conclusion

So, just like many other folks across the U.S. and abroad have been conditioned to do what everyone else does, and simply throw away all of the leaves raked from their yards, they also simply throw away all of their precious wood ash, right out into the trash!

You can do this too, it's certainly the path of least resistance. However, it is not sustainable. Just think what has to happen instead when you want to purchase lime. You need to get in the car, drive to the store, pay five to ten dollars for a bag of lime and then use it and store the remainder in the shed. In order to get that lime to the store it needs to mined/produced/packaged and then shipped via diesel trucks all across the country.

Doesn't that seem a little work intensive? This is especially true when you consider what has to happen to fuel the trucks that deliver the lime to the stores. In addition, other large diesel trash trucks will need to cart your ashes to a landfill when you dispose of them. Ouch. Stop the planet and let me off. Also, how much is involved for you to earn the five or ten dollars in the first place? That amount of cash may seem relatively small, but how is your thinking process in regard to this? Several of these smaller five to ten dollar expenses, if unnecessary, really will add up and can spell the difference between having to work an extra few hours or not. We need to really think 'sustainably' in all things.

Instead, by saving two whole steps, you can 'lime' with the ash that you already have. By using the ashes from the fireplace, as you get them, you can easily distribute them and let the soil slowly begin to ingest it into its intricate web of life.

You will also have the added satisfaction of knowing that you are in complete control of what goes into your ash.