Material % Nitrogen % Phos. % Potassium
Alfalfa meal 2.5 0.5 2.1
Bone meal (raw) 3.5 21.0 0.2
Bone meal (steamed) 2.0 21.0 0.2
Chicken manure (pure, fresh) 2.6 1.25 0.75
Cottonseed meal 7.0 3.0 2.0
Blood meal 12.0 3.0 --
Fish meal 8.0 7.0 --
Greensand -- 1.5 7.0
Hoof and Horn 12.5 2.0 --
Kelp meal 1.5 0.75 4.9
Peanut meal 3.6 0.7 0.5
Tankage 11.0 5.0 --
Growing most types of vegetables requires building a level of soil
fertility that is much higher than required by field crops like
cereals, soybeans, cotton and sunflowers. Field crops can be
acceptably productive on ordinary soils without fertilization.
However, because we have managed our farm soils as depreciating
industrial assets rather than as relatively immortal living bodies,
their ability to deliver plant nutrients has declined and the
average farmer usually must add additional nutrients in the form of
concentrated, rapidly-releasing fertilizers if they are going to
grow a profitable crop.
Vegetables are much more demanding than field crops. They have long
been adapted to growing on potent composts or strong manures like
fresh horse manure or chicken manure. Planted and nourished like
wheat, most would refuse to grow or if they did survive in a wheat
field, vegetables would not produce the succulent, tender parts we
consider valuable.
Building higher than normal levels of plant nutrients can be done
with large additions of potent compost and manure. In semi-arid
parts of the country where vegetation holds a beneficial ratio of
calcium to potassium food grown that way will be quite nutritious.
In areas of heavier rainfall, increasing soil fertility to vegetable
levels is accomplished better with fertilizers. The data in the
previous section gives strong reasons for many gardeners to limit
the addition of organic matter in soil to a level that maintains a
healthy soil ecology and acceptable tilth. Instead of supplementing
compost with low quality chemical fertilizers, I recommend making
and using a complete organic fertilizer mix to increase mineral
fertility.