[chickpeacurry]

What would I use this for to add to the soil or a feeder. I have read good reports but not sure what vegetables I would use it on and how. Thanks

[Annen]

As I understand it, it is a top dressing for the whole garden.  It is supposed to replace minerals that get leached out over the years.
I might be wrong, but that is how I am using mine.

[Kristen]

If it Volcanic Rock, or Rock Dust (which I presume is the "sweepings" off the quarry floor)

Maybe they perform the same though??

[JayG]

One of the big suppliers of Rock Dust got into trouble with the Advertising Standards Authority for making claims they couldn't substantiate with evidence from field trials.

That doesn't mean it doesn't do anything - it's been discussed on here a few times and definitely has its supporters - for me it's a question of whether your soil is actually deficient in the types of minerals provided by the product, and it would be a very expensive undertaking to have it tested to find out.
(You could use that as an argument for using Rock Dust anyway, as the cheaper option!  )

[Nobbie]

What would I use this for to add to the soil or a feeder. I have read good reports but not sure what vegetables I would use it on and how. Thanks

What sort of soil do you have? How well do your current crops grow? Why do you think you need it?

[solway cropper]

I'd agree with JayG. It may well provide additional trace elements but unless your soil is deficient then it's a waste of money. On a light sandy soil where nutrients are readily leached out it may be beneficial but if you garden on a clay/loam soil and apply plenty of organic matter it will make no difference. When something new comes along you should always ask: will do anything that I can't already do?

[Kristen]

I bought a bag or Rock Dust a while back.  The amount stated for the "Initial treatment" is significant, and thus expensive.  I did try doing half-and-half as an experiment to see if the crops grew better, but I only sprinkled a bit around the plants and wasn't motivated enough to keep decent records.  I have read of plenty of people who swear by it though, and they are accomplished growers, so likely to already have their soil in good heart and be using plenty of organic matter.

I'd like to use less petroleum derived fertilisers, and mined Phosphates ("none" would be better still) [I'm assuming that rock dust is a by-product].   Rock Dust isn't a help for NPK though ... maybe combined with urine harvesting or somesuch - although I find the thought of retro fitting that to my house, and the "processing", rather off putting!

Sorry if you were eating your breakfast