Quote Originally Posted by urbanfarmer
For example, potassium can be added by using wood ash from a fire.
Not saying don't do this. Urbanfarmer is correct. Wood ashes WILL boost potassium levels. But they are EXTREMELY caustic and can raise your pH levels very rapidly, so be circumspect and scientific if you choose this route!

One of my other hobbies is homemade cold process soap making. Wood ashes soaked in water have been used for centuries in place of lye in soap making. A five gallon bucket filled with ashes and water can burn your hands just like lye! I routinely save my natural lump charcoal ashes from my grill, soak them in water and use the solution sparingly on my bananna trees which are phosphorus hogs. But I also have to use sprinkled sulpher in addition to the ash water when i do so in order to keep the soil pH from rising too high. Out of curiosity, I once rendered several gallons of wood ash water into a significant quantity of sodium carbonate and nearly a half ounce (by volume) of potassium carbonate (pure potash). Both are highly caustic.

Best bet is to make the ash/water solution, measure the pH, then calculate how much of a pH increase the addition of the ash water will cause, then add it SLOWLY - over time - so as not to screw up your system's pH all at once!

Just sayin'...