Q:  I had my soil tested by the UGA Soils Lab. They recommended I apply 6 lb. of 15-0-15 to my garden. However, no garden centers carry 15-0-15 in my area. What else can I use?

A: With the multitude of fertilizer analyses available at garden centers, it’s tough for the soils lab to make a recommendation based on what you can find locally. Instead, they make their advice based on soil science and hope that fertilizer manufacturers will make the fertilizers that fit a given population.

Knowing that converting one analysis to another requires math skills most folks don’t have, the soils lab has published a handy online calculator that does all the work for you.

I went to a local store and found the following products:
24-24-4
32-0-10
29-0-4
12-12-12
24-4-11
10-10-10
13-13-13
21-0-0
11-2-2
16-4-8
0-0-60

While the 32-0-10 could be used if you cut your 15-0-15 recommendation in half and the 24-4-11 and 16-4-8 might also be appropriate, the calculator found an exact recommendation: 4.3 lb. of 21-0-0 plus 1.5 lb. of 0-0-60 per 1000 sq. ft.
Click here for the online calculator.