Using Rock Dust

**Aberdeenplotter** · 10-12-2012, 12:00 PM

I have used it but without a controlled comparrison so although I cropped very well from the area treated, I don't know if the rock dust affected anything

**VirginVegGrower** · 10-12-2012, 02:38 PM

I too used rock dust with success, both on my onion bed and on my fruit bed. Last growing season was the first year I could say I had large sized onions. They had no feed, whereas the other half sized bed had spring feed and no rockdust. They were considerably smaller onions. The fruit bed had a great return on the currants this year, whereas previous years the yield was minimal, but they were newly planted I suppose, so can't really draw too much there. The strawberries, newly planted have gone mad. All in all I would say Rockdust improved my onions without doubt (sounds so rude), but like AP says, it wasn't a controlled experiment. I will be buying some again next year and it will be spread onto two more beds. You are not supposed to add it every year, but every few years. I spoke with the company owners this year at the Edible Show and they had an offer on at the time for two bags, so maybe wait until then, if you are attending - it's probably a regular stand.

**mothhawk** · 10-12-2012, 07:30 PM

I live less than a mile from a granite quarry (quartz diorite), so when the wind is in the right direction on blasting day I get free extremely finely distributed rock dust - on everything!

(Hope it's not Fingal's cave the Scots are grinding to dust

)

**Aberdeenplotter** · 10-12-2012, 07:41 PM

I'm not sure if granite dust is the kinda dust with humate which I understand to be the active ingredient in quarry dust that encourages root growth.

Humate: Humate is a generic name for humic materials � salt forms of humic acid. They are most commonly low grade lignite coal. Humates regulate water-holding capacity, have extremely high ion exchange capacities, and reduce soil erosion by increasing the cohesive forces of the very fine soil particles. Very low concentrations of humates have been shown to stimulate seed germination and root growth. They have also been shown to stimulate desirable soil microorganisms. The percentage of humic acid in a humate will vary from product to product.
Humates may be made into liquid form or used in the dry form.

**Aberdeenplotter** · 10-12-2012, 07:49 PM

whoops amazing what you can find in a few minutes on google

Granite Sand: Sand-like residue from the granite quarry or natural deposits. Excellent way to add minerals to planting beds. Much better than washed concrete sand. Contains 5% potash and many trace minerals. Also has paramagnetism, but less than lava sand. Approximate analysis is 0-0-5. Granite is a low cost source of minerals, especially potash. It is sand-like residue from the granite quarry or natural deposits. Granite dust or granite stone meal is a natural energy and potash source. Its potash content varies between 3 and 5 percent and it contains valuable trace mineral elements. Granite dust can be used as a topdressing or worked directly into the soil. In the garden, suggested rates of application are 10-100 pounds per 1000 square feet; on the farm, 1 to 2 tons per acre.
Research at Garden-Ville farm proved granite sand very beneficial. It made southern peas turn green in an 8.3 pH soil. Peas nearby with same growing conditions but no granite sand remained chlorotic and had poor growth.

**mothhawk** · 10-12-2012, 07:52 PM

So how do you get humates from igneous rock? Lignite is a very close relation of peat, isn't it? So bound to benefit the soil.

**mothhawk** · 10-12-2012, 07:54 PM

Originally posted by Aberdeenplotter View Post

whoops amazing what you can find in a few minutes on google

Granite Sand: Sand-like residue from the granite quarry or natural deposits. Excellent way to add minerals to planting beds. Much better than washed concrete sand. Contains 5% potash and many trace minerals. Also has paramagnetism, but less than lava sand. Approximate analysis is 0-0-5. Granite is a low cost source of minerals, especially potash. It is sand-like residue from the granite quarry or natural deposits. Granite dust or granite stone meal is a natural energy and potash source. Its potash content varies between 3 and 5 percent and it contains valuable trace mineral elements. Granite dust can be used as a topdressing or worked directly into the soil. In the garden, suggested rates of application are 10-100 pounds per 1000 square feet; on the farm, 1 to 2 tons per acre.
Research at Garden-Ville farm proved granite sand very beneficial. It made southern peas turn green in an 8.3 pH soil. Peas nearby with same growing conditions but no granite sand remained chlorotic and had poor growth.

Crikey, I'll have to nip down into the pit with a bucket and shovel early in the morning before they start work then!

**VirginVegGrower** · 10-12-2012, 08:12 PM

Crikey I'll have to come up and visit

**j r hilton** · 11-12-2012, 02:22 PM

It seems it may be worth trying. Nothing to lose really and maybe a lot to gain. I will just have to find out where to buy some.Thanks for the replies.

**Aberdeenplotter** · 11-12-2012, 03:49 PM

One supplier here Rock Dust 20 Kg Bag - Harrod Horticultural (UK) but there will be others

**scarletrunner** · 11-12-2012, 07:10 PM

Available at B@Q.

**VirginVegGrower** · 26-12-2012, 05:31 PM

Well Santa brought me some for my birthday and I've used it today to sprinkle some Santa magic dust all over my polytunnel beds. He's a clever ole Santa

Thank you xxx

**Madasafish** · 27-12-2012, 10:53 AM

I bought 2 x 10kg bags from B&Q. (in their sale and Diamond card of course.)

Controlled experiment on tomatoes,rasps and strawberries in 2013..

**VirginVegGrower** · 27-12-2012, 10:55 AM

Sounds exciting Madasafish. I shall be interested in the results.

Announcement

Using Rock Dust

Using Rock Dust

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Latest Topics

Recent Blog Posts