We save up our winter fireplace ashes in a tin trash pail. The Eldest claims "it's a Roman thing" because ancient Roman scientists and scholars documented the value of returning ash to the land.
In the 18th century, the benefits of ash-derived potash, or potassium carbonate, became widely recognized. North American trees were felled, burned and the ash was exported to Great Britain as "potash fever" hit.
It gets better. In 1790, the newly-independent United States of America's first patented process was a method for making fertilizer from wood ash (U.S. patent number 1: "An improved method of making pot and pearl ash)." But cheaper sources of lime and potassium eventually killed the commercial market for wood ash.
In our case, what could be cheaper than fireplace ashes? It's so simple it stings. All you need is a fireplace (indoor or outdoor) and a mini tin trash pail with a lid.
This past winter's wood ash.
Ash is so very fine and light to the touch. Unlike sand, which tends to be heavy, ash blows away easily, so you wait for a non-windy day to apply wood ash to your garden soil.
Please don't try to use a plastic trash can or bucket for this- ash stays hot for a long time after burning out. You will find yourself with a perforated wood ash pail. Stick to metals and materials with high melting points.
Also, there are certain variables and restrictions to using wood ash as a garden fertilizer. It works well in our clay-heavy soil, but plants like blueberries and rhododendrons don't take kindly to the increased alkalinity. Weekend Gardener has all the do's and don'ts on using wood ash.
