On 10/5/2008 10:07 AM, Vegegrower wrote:
I got a B&Q soil tester and it indicated the soil was about PH 9, dark
green on the package scale indicator.

I only grow vegetables such as potatoes, onions, leeks, turnips and the
like and I need to know how much sulphur per square yard or meter do I
have to add to reduce the PH of the soil to get it slightly acidic
which it seems is ideal for popular vegetables.

Can any one advise on the amount of sulphur to use please?

many thanks

I use about a handful per square yard about once or twice a year. It
takes a while for sulfur to acidify soil. Bacteria in the soil slowly
convert the sulfur into sulfuric acid.

However, I also use acidic fertilizers. These include ammonium sulfate
(very strong, use sparingly) and iron sulfate. I also use very slight
amounts of zinc sulfate around citrus and a gardenia and magnesium
sulfate (Epsom salts) around my roses. All of these work rather
quickly. Unlike plain sulfur, they can readily leach away and might
need frequent renewal.

Calcium sulfate (gypsum) is only weakly acidic. I use that to improve
my adobe clay, even around plants that prefer an alkaline soil (e.g.,
dianthus, iris, primroses).

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/