[Terrapreta] CORRECTION re: Terra preta 101

[Allan Balliett]

Mihael Bailes said:

>Charcoal will lower pH. Ash will lower it drastically


Like I often do, I think you flipped a bit on what moves soil sweet 
and what moves it sour.

Here's a comment from the U of Conn on the affects of wood ash on garden soils:

>Wood ash acts on the soil much like limestone in that it raises the 
>pH or alkalinity of the soil. Consequently, many wood stove burners 
>dump the ashes on their garden site with the thought that they are 
>improving the soil condition of their garden. Yet unlike limestone, 
>which can take six months sunfloweror more to take effect, wood ash 
>has high water solubility and quickly changes the soil pH. This can 
>cause a problem with raising the soil pH over the optimum level of 
>6.5 to 7.0 if we spread too many ashes in the same area. A soil pH 
>over the optimum level can affect plants as adversely as a pH that 
>is too low. High pH will limit the uptake of important soil 
>nutrients needed by the plant such as phosphorous, iron, and 
>magnesium.

I'm here to tell you: you don't want to get your soil pH higher than 
7.5 if you want your gardening efforts to be productive.

Here's a perhaps off-topic question for you soil scientists: what is 
the relationship between "alkalinity" and 'pH'? I've been lowering 
the pH of my well water (8.2) with the addition of vinegar for foliar 
spraying and find that test strips may show a pH of 6.0 but we are 
still over the top on alkalinity, even if I add an agricultural soil 
softener and bring us into the test strip 'soft' range.

-Allan Balliett
Fresh and Local CSA
Shepherdstown, WV