Estimate fertilzer needs by observation?

[Vanisle_BC]

Thanks Dylan. I've applied a little greensand before but it's pretty expensive in any quantity. I can get it from bulk bins near-locally. I liked the idea that its granularity might improve the texture & drainage of clay-ey soil as well as adding potassium. I probably didn't use enough of it to make much difference.

Are we talking the same stuff? What I got was a grey, very fine-grained sand.