Chemical fertilizers and organic fertilizers show their nutrient content with
three bold numbers on the package. These numbers represent three different
compounds: Nitrogen, Phosphorous, and Potash (Potassium), which we can also
describe with the letters N-P-K. The three numbers listed on fertilizer labels
correspond to the percentage of these materials found in the fertilizer. What
does each nutrient do? In addition to other properties, Nitrogen helps plant
foliage to grow strong. Phosphorous helps roots and flowers grow and develop.
Potassium (Potash) is important for overall plant health. Be aware that high
nitrogen fertilizers will make for quick growth but weaker plants that are more
susceptible to attacks by diseases and pests. Fast, showy growth is not
necessarily the best thing for your plants.
German scientist Justus Von Liebig was responsible for the theory that
Nitrogen, Phosphorous, and Potassium levels are the basis for determining
healthy plant growth. However, this theory, which dates to the 1800s, doesn't
take into account the dozens of other nutrients and elements that are essential
to plant growth such as sulfur, hydrogen, oxygen, carbon, magnesium, etc. Nor
does the theory talk about the importance of beneficial soil organisms that help
your plants to flourish and to fight off pests and diseases.
While Von Liebig's work was unquestionably important to the science of plant
growth and agriculture, other ways of looking at how plants utilize nutrients
have largely been ignored, especially by those companies who produce the
chemical fertilizers commonly on the market today. For example, if you properly
aerate the soil, earthworms, beneficial microbes, and other critters found
underneath your garden and lawn will have better access to the oxygen they need
to thrive. As they live and digest organic matter, they help to create soil that
is healthy and fertile. Healthy soil is the basis for healthy plants.
Additionally, if we look at nature, compost in the form of organic humus is ever
present in natural plant communities, providing lots of the nutrients that
plants need to grow and thrive. Compost contains Nitrogen, Phosphorous,
Potassium, and a great abundance of other trace elements that will benefit your
plants.
It is clear that Nitrogen, Phosphorous, and Potassium are not necessarily the
most important elements you need for your plants to grow well. In fact, elements
such as carbon, hydrogen, oxygen, sulfur, magnesium, copper, cobalt, sodium,
boron, molybdenum, and zinc are just as important to plant development as N-P-K.
(Source: http://www.utexas.edu/utpress/excerpts/exgarhow.html) Over the years,
Justus Von Liebig's theory developed into the dominant paradigm for how we grow
our ornamental and edible plants. The bad news is that this has lead to a vast
amount excess nutrients building up in our streams, lakes, and rivers, because
chemical fertilizers are often over-applied. Surprisingly, much of this overuse
of chemical fertilizers is actually from homeowners, and not from farmers, who
typically carefully measure and apply the least amount of fertilizer necessary
to get the job done in order to grow their crops in the most cost effective way
possible.
Many homeowners who aren't growing to make a profit end up inadvertently
overusing chemical fertilizers (and pesticides too!). They think that if a
little bit is good, then more must be better. It isn't! According to the
National Academy of Sciences, even though farmers uses pesticides more widely,
homeowners uses 10 times more fertilizer per acre. If you only take away one
thing from this article, please let it be that you should only use the proper
amount of any fertilizer, and not anything more. This will save you money, and
it will also keep your yard and garden healthier at the same time. This is
extremely important with chemicals, but it also applies to organics! Organic
gardeners can look to the work of Sir Albert Howard for solid research and ideas
on how to grow plants more naturally. His ideas consider chemical processes that
occur in nature. He then applies them to agriculture and home gardening.
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