Monday, February 27, 2006

Rock dust

I am still busy weeding and shovelling mushroom compost about, which doesn't make for very interesting posts.
However it has been allowing me to get a good look at my soil. A couple of years ago I visited the SEER centre near Blairgowrie where they have been experimenting with re-mineralisation of soil by adding in ground rock dust. The results are certainly impressive - bleak moorland has been transformed into a verdant garden full of giant vegetables. Experiments by other horticultural organisations have also found that the rockdust seems to be doing something - seedling deaths are fewer, plants more robust, vegetable yields higher.
Over the past 2 years I have added in 16 tons of rockdust into our raised beds - I used basalt from the Tarmac quarry near Dumbarton - and I believe that it makes a difference, particularly to the growth of bulbs. The tulips in the beds with rock dust were on average 4 inches taller than those grown in the beds without dust. My methods aren't exactly scientific - the dust also lightens the soil and improves drainage which may have an effect - but I believe that it is certainly worth it and a single application of rock dust should last several years as it gradually grinds down and gets incorporated into the soil.
One of the problems that domestic gardeners have had is that it is difficult to get hold of rock dust in small quantities. Now the SEER centre has begun to market bags of dust which are on sale at certain garden centres. I think that with worries about the lack of minerals in our vegetables that it is well worth digging in a bag or two to your vegetable patch.
For much, much more information (and for all the science) look at

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