I use greensand on my vegetable gardens and around my
roses. It is best applied in the fall, as it takes about 6 months for it to become available to the
plants, but I have applied it in the
spring also. It lasts a long time. I till it into my garden every 5 years or so, and some reports say it can last up to 10 years.
The application rates are 10 pounds per 100 square feet on soil low in potassium, 5 pounds for soils with average fertility, and 2 1/2 pounds to maintain production in productive, fertile soil. It's best to have a soil test done to determine soil fertility levels.
I mix my own
rose fertilizer out of various organic fertilizers, including greensand, (applied monthly during the
growing season) Then, after the first frost in fall, but before the ground freezes, I sprinkle 1/4 c. greensand around each
plant.