I always knew the Brits were crazy.
Given the justifiable panic over the Tennessee fly ash spill here in the States, it’s almost impossible to believe that people might put anything remotely resembling coal by-products in their gardens on purpose, but they do.
Sounds nuts, I know, but experiments have been ongoing in experiments have been conducted in India, Australia, China, and the United States, Poland, Thailand, and who knows, maybe the North Pole, growing vegetables (or in China, trees) in soil amended with bottom ash. Since ash is almost always quite alkaline (pH>9), this only makes sense in soils that have low pHs, but in those it can raise pH, improve water retention, improve mineralization, and increase nutrient availability. And at normal agricultural application rates (20 tons or more (!) or so on each hectare, which is about 2.5 acres) virtually all of experiments I’ve looked at show that these unlikely amendments are not accumulating at dangerous levels in plants.
Given my suspicious nature, my organic roots, my alkaline soil, and the fact that I haven’t had time to check on who’s funding these experiments, I’m not about to rush out to purchase coal ash for my garden.
Apparently, though, that’s exactly what some people in the U.K. do. A prime source appears to be one’s local chimney sweep, who clears chimneys of soot, then sells it to local gardeners. Soot wouldn’t be bottom ash, and I’m not sure off-hand which of the five or so commercial coal combustion by-products it would most resemble. (I’m not going to take the time to look it up now, since I’m once again late with a major article, and hoping to keep my job.)
But I’m wondering—what exactly is going on? Are people growing vegetables in the gardens on which coal soot gets deposited? Are people who use soot also using coal ash? Has this soil been tested? Come on, all you over there on that island, pipe up. Enlighten us.