WHERE IT ALL BEGINS: THE SOIL - Growing Chinese Vegetables in Your Own Backyard - page 210

natural tendency toward one or the other. In Connecticut, for instance, most soil was
originally acidic. The Connecticut gardener can't count on this, though, because gen-
erations of farmers have worked to correct this acidity, plus areas on top of limestone
outcrops may be naturally alkaline.
Most vegetables prefer a pH between 6.3 and 6.8, or slightly acidic, because that's
the range of maximum nutrient availability. If soil contains ample organic matter to buf-
fer pH, plants will tolerate a wider range. Snow peas and watercress prefer a slightly
alkaline soil.
If a soil test shows your soil is too acidic (below 6.0) or too alkaline (above 7.5),
the next step is to bring it to the desired pH. Always do so gradually, with several small
applications rather than a single large one, or you'll end up with more of a problem than
you started with. If your soil is too acidic, add ground limestone; follow the application
rates on the label. Wood ashes can also be used to raise the soil pH.
If your soil is too alkaline, add sulfur along with organic material. Use acidic forms
of organic matter, which include peat moss, ground bark, and sawdust. If you have ac-
cess to pine needles, they make an excellent mulch.
Adding organic material every year helps correct either acidic or alkaline soils be-
cause it is an excellent buffer. In addition, it encourages the growth of soil bacteria and
earthworms and decomposes into humus, which improves the texture of the soil and
slowly fertilizes it as well.
Just What Is Fertilizer?
There's no coincidence that fertility and fertilizers are related. Fertilizers help you give
back what plants remove from the soil, which you in turn remove when you harvest
plants. There are three primary nutrients in most bags of fertilizer: nitrogen (N), phos-
phorus (P), and potassium (K). The numbers on the bags (for instance, 7-7-2 or 5-10-5)
give the percentage, in NPK order, of these three nutrients that the mixture contains.
Each element has its particular function in plant growth, just as certain nutrients con-
tribute to the health of certain parts of the human body (for instance, the calcium in milk
builds bones while the iron in spinach contributes to the red blood cells).
Traditional, synthetic fertilizer blends tend to have higher analysis numbers such as
5-10-5 or 5-10-10. Organic fertilizer mixes tend to have lower numbers, but these don't
tell the whole story. Synthetic blends often contain only N, P, and K and are designed to
release these nutrients as quickly as possible. They may be called “balanced” or “com-
plete” because they contain these three elements, but they don't contain all the essential
nutrients. Because they are made from natural substances, organic fertilizers also con-
tain micronutrients, which are also essential to plant growth.