I have just found this stuff called 'root-out' at the garden centre, it is for killing tree stumps etc. Has anyone ever found out if this is KNO3 because it does not have 'ingredients' on the box, surprisingly. What it does say is that it hydrolises in the soil to form NH4 and releases nitrogen, which I can understand (but it doesnt say anything about potassium), does KNO3 do this??, also I have some dusting sulphur but its green! will this impurity (whatever it is) affect the bp??
Thanks
Marcus.
'Root out' products are always one oxidiser or another, w/ potassium nitrate being the most common I believe, but it may have other chemicals as well.
I checked 3 and found two were 99% and 100%.
The third was sodium metabisulfite 90%, sulfur 10%
Even if the label doesn't list ingredients per se, it should at least have a code for it's hazmat content, In the States it's called a Material Data Safety Sheet, or MSDS.
for example, the Material Data Safety Sheet for one stump remover lists:
Potassium nitrate 7757-79-1 99%
I checked 3 and found two were 99% and 100%.
The third was sodium metabisulfite 90% ?

, sulfur 10%
Sorry, searching for 'root-out' gets me references to evil and terrorists.
so you should be able to find reasonble purity.
I assume MSDS has an equivilent there.
As for green sulfur, I'd keep shopping.
It likely has chemical wetting agents in addition to some bentonite (for spreadablity I think) mixed in to the tune of 10%.
I use dusting sulfur that I know is 92% with 8% bentonite (but it isn't green?) for non critical things like increasing ignitablity of sugar-based rocket fuels, smoke etc.
BP is an art and a science, and practicing art with contaminated science will affect your art, and not for the better.
My BP improved considerably when I got some 99%+ sulfur.
I am not saying agriculturial sulfur won't work, mine did OK, but green

? I havn't a guess what they may have added there.