huge melons from rock dust

I saw this on the BBC news yesterday: "Cameron and Moira Thomson ... have been battling to prove that rock dust can replace the minerals that have been lost to the earth over the past 10,000 years and, as a result, rejuvenate the land and halt climate change. To prove their point, the couple have converted six acres of open, infertile land in the Grampian foothills near Pitlochry into a modern Eden. Using little more than rock dust mixed with compost, they have created rich, deep soils capable of producing cabbages the size of footballs, onions bigger than coconuts and gooseberries as big as plums."



Assuming that there was no sleight of hand going on then the pictures we saw of the veg produced was amazing. At first sight this looks like a magic bullet. Perhaps there are downsides, probably there are. I wonder what they might be?

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