Agriculture Reference
In-Depth Information
availability throughout the season. The following tables show
the amount of a given organic fertilizer to use given a certain
soil test result. In the case of nitrogen, the table takes
biological activity into account. Because the amount of
nitrogen needed is lower for root crops, the results are shown
with a slash between them, with leaf and fruit crops as the
first number and root crops as the second number.
Compounding Your Own Fertilizer
The foregoing numbers are interesting, but not very useful by
themselves because you can't go down to the store and buy
five ounces of phosphorus or three ounces of potassium. In
fact, in their pure forms, phosphorus is poisonous and
incendiary and potassium will explode on contact with
moisture. Instead, you'll need to figure out a mix of natural
substances that will give you what you need. I have never
found a topic or website that goes beyond listing the NPK
values of various natural substances and actually teaches you
how to combine them to get what you need. All it takes is a
little math, which, in an era of scientific calculators and
computerized spreadsheets, isn't really a problem. First, here
is a table listing the NPK values of various substances used as
natural fertilizers. Keep in mind that this table is an average
of various brands, whose composition varies. If you buy a bag
of bone meal and it lists different numbers, use those numbers
instead of those in the table. The table is most useful for
things that don't usually have numbers—such as wood ashes
or alfalfa meal.
