If you have spare ashes lying around from a backyard firIe pit, recycle some of it into your soil.
Why might ashes be good for the garden?
Depending on source, wood and plant ashes contain varying amounts of potassium, phosphorus, magnesium and micronutrients. Calcium is the most abundant element in wood ash so it acts somewhat like agricultural lime. In fact, it is stronger than lime. You would think the obvious use for ashes then would be to adjust soil pH.
As I explained earlier in the book, I don’t test my soil’s pH because if I have enough organic matter in the soil, the pH should be at a range that supports most all edibles that I want to grow. Another key for worrying less about pH is MODERATION. Keep the soil in balance by not overdoing any one material.
My goals for using ash in the garden are long term only. I get to recycle the ash and it will improve soil fertility over time. I believe ashes help keep water in the soil which in turn helps nutrients work more efficiently with each other. I’ve also added ash to the compost pile.
Where do I find wood and plant ashes?
Ashes from hardwoods (oak) and softwoods (pine) can be used in the garden. Hardwoods will contain more nutrients than the same amount of softwood ashes.
Do not use ashes from treated, stained or pressed wood products. Particle board contains glues and formaldehyde. I would also not use wood ashes from wood that had any kind of fire starter poured on it.
Charred plant matter can be used in the garden as well. I tend to forget things in the oven so I’m a veteran of burned plant matter – otherwise known as dinner at my house!
I’ve used burned kale chips and citrus peels, both the casualties of too much going on. My daughter harps that multi-tasking is unhealthy. So I ask her with a smile, “Would you like to eat dinner tonight OR get help on your science project?”
Which plants may benefit from wood and plant ashes?
Cabbage, broccoli, kale, kohlrabi and collards may benefit from soil amended with ash. Young plants or newly emerged seedlings could be damaged by ash. It’s best added to the soil before planting.
Compost in small amounts. Maybe urine – go to the Bibliography and topic of Wood Ash to access a reference from Science Daily and the American Chemical Society on the use of wood ash and urine together.
Recipe for using Wood or Plant Ashes in the Edible Garden
I can’t stress enough that if you use too much ash in your garden, you risk killing your plants and damaging your soil. So, please use it in moderation and when in doubt use less than more.
I place the ash in a plastic bag and crush with a brick or rock. Smaller pieces will make it less concentrated and easier to disperse.
Use gloves and a dust mask unless you can be super careful not to touch it with your bare hands or breathe in dust particles. Don’t work with ash on dry, windy days.
Three cups of crushed ash works well for a raised bed measuring 8 feet x 4 feet. The nutrients in wood ash leach out faster than lime.
The best time to apply ash is before you plant, at least a couple of months out. This could mean late fall or early spring. Disperse it evenly and rake it in under the surface.
If using ash in tandem with urine, work the ash into the soil first. Click here to go to the Urine Recipes.
Wood and Plant Ashes Quick Tips
- Two hundred years ago, ash was processed for use as a potash fertilizer source. Eventually, the production became more costly and new methods to produce potash were developed.
- Avoid leaving ash on the surface. It is more effective when it contacts the soil.
- Fresh ash could still be “live”. Only use ash that is cool and completely burned-out to prevent skin burns and a fire hazard.