How to Grow More Vegetables : And Fruits, Nuts ... - Shroomery

52 FERTILIZATION
rainfall, altitude, sun exposure, drainage conditions, the types of
crops grown, and cation-exchange capacity, no standard added
nutrient formula will work in all situations.
If you can, test your soil for major nutrients and trace minerals,
including pH (the acidity or alkalinity level of your soil),
before choosing fertilizers. The major minerals, those that
plants utilize in relatively large amounts, include nitrogen, phosphorus,
potassium, sulfur, magnesium, and calcium. Trace
minerals—such as zinc, boron, copper, and iron—are important
elements that are required in very small quantities. For professional
soil testing, we use the Timberleaf soil testing service. 4
It specializes in testing for organic farmers and gardeners, with
an emphasis on Biointensive fertility. The service analyzes all
soil and plant minerals and the soil’s physical characteristics
and can provide follow-up review and advice on your year’s
experience in the garden. If you are unable to arrange a professional
soil test, purchase a home test kit. The best such kit is
the La Motte kit. 5 With the home kit you will be limited to
testing nitrogen, phosphorus and potassium content, and pH.
To take a soil sample from your yard, use a nonferrous
trowel or a stainless steel spoon to dig a vertical soil slice from
8 inches below the surface. Take samples from 6 to 8 representative
areas and mix them together well in a clean plastic
bucket. Make sure you do not include residues, such as roots
and surface organic litter, in the composite sample. Also, do not
sample for 30 days after adding any fertilizers, manure, or
compost to the area. The samples normally should be taken at
the end of a growing season or just before one. You will need a
total soil volume of 1 pound for professional testing or 4
heaping tablespoons for the home test kit. Remember that soil
tests can save you a lot of money, since they all guard against
overapplication of fertilizers, allow you to account for nutrients
already available in your soil for good plant growth, and
increase yields.
To use the Timberleaf service, ship your composite sample
as instructed in its soil test packet without drying the soil. For
a home test kit, let samples dry in a small paper bag in indirect
sunlight—not in the sun or an oven. When you are ready to
begin testing, follow the included with the kit. Record home
test results on a photocopy of the chart on page 50. Once you
have completed the test, use the information page 45 to determine
a general fertilization plan for your garden.
As you become more skilled, you may want to use John
Beeby’s book Test Your Soil with Plants to test your soil. This is
how people used to learn about their soil’s nutrient needs for
thousands of years before chemical soil tests became available.
Eventually each of us should have a living soil test of plants
4. Timberleaf, 39648 Old Spring Road, Murieta, CA 92563-5566.
5. La Motte Chemical Products, Box 329, Chestertown, MD 21620: Model STH.