[GreyScales]

This has been a subject of confusion for me for some time and the customer query e-mail sections at online retailers have never responded to this question. I've noticed the price of rock dust can vary greatly between sellers, despite at face value essentially selling the same product. It makes me wonder if there are different quality versions, but if that's the case wouldn't they be eager to defend their product against inferior options?

I mean, what's essentially the difference between the 10kg for £19.95 at QuickCrop or the 10kg for £5.98 at B&Q? Are these all essentially the same product and it's a case of just getting the cheapest, or are these price differences justified in some way?

[mumofstig]

It's all dust from quarries around the country - different rocks contain different minerals, so they will differ - but which is best?

I don't know enough about it to say 

[JayG]

It's a waste of money at any price if it doesn't 'work' - try to find some independent research into the benefits of rock dust in general before trying to choose any particular brand.

[solway cropper]

The B+Q stuff comes from the same place as the better known SEER rockdust so it should be the same stuff at a much cheaper price. The trace elements it claims to add will be available in most normal soils unless they have been intensively worked and had nothing put back. As JayG says, check to see if you actually need it before parting with your hard-earned.

[GreyScales]

There seems to be quite contrasting views on rock dust. There are people such as in this instance who say it's useless, were as I've spoken to people who claim it makes a difference even in potting mix; which even I find doubtful. I'd be sceptical of any research that looks at it from the agricultural industries perspective, because they rely primarily on chemicals and intensive farming that damages the soil life responsible for actually breaking this stuff down. So it may be useless when done on an industrial scale, but organic plot owners who feed the soil rather than the plant may see benefits in the long run. At least that's my hypothesis.

So I suppose my question to those who do use it is whether it's a matter of just getting the cheapest option, or whether they know there is something to the significantly higher price tag?

[New shoot]

Rock dust research does tend to concentrate on the success stories.  In Australia for example, a lot of soils are well weathered mud and clay and contain very little rock.  The addition of rock dust has added a lot of trace elements and plants have suddenly taken off.

In the UK, the ice ages the land has experienced have ground up vast quantities of rock and distributed into our soils.  The use of rock dust here to create soils has shown results, but whether it will add much to already fertile land is another question.

Why not try some of the cheaper stuff and see what you think before investing ?  It would be a simple experiment to add it to potting mix and trial a crop grown with or without it, or do the same for a crop in the ground.

Personally, and I am not claiming any great wisdom on soil science here, but I think adding organic matter back into the soil would show greater returns - short term and long term

[mumofstig]

I ask myself the question - if the soil still had all the nutrients from the ice age, why would we get yellow leaves (often magnesium deficiency) brown bits in our swede (boron deficiency) etc etc

So IMO adding a natural replacement, to soil that has been cropped for many years eg an allotment, can do no harm at all