Yesterday, I wrote about garden pesticides, so I figure today I might as well cover chemical fertilizers.
Just like pesticides, I used to use these fertilizers all the time as a landscaper and on the golf course.
Even today, there are a couple of lesser-known chemical fertilizers that can be extremely useful in an otherwise organic garden when you're trying to bring back a badly abused soil, but for the most part, we need to stay away from them.
What's Wrong With Chemical Fertilizers?
When we look at chemical fertilizer and the environment, the interesting thing is that they are potentially just as damaging to the soil as pesticides. They undergo chemical reactions in the soil that can produce acids with a pH lower than 1.2 or bases with a pH above 11, both of which are extremely toxic to pretty much any living being.
Even the chemical fertilizers themselves, which are salts, either destroy or interfere with the cell walls of microbes, hurting or killing them. These synthetic fertilizers contain a lot of hydrogen, which kicks minerals out of the soil, depleting the soil of nutrients with repeated use.
Plants and microbes use hydrogen for this purpose, too, but in a much more controlled fashion.
Interestingly, oxygen produces one of the detrimental chemical fertilizer effects. It's created during this chemical reaction and organic matter is burned up. Some synthetic fertilizers even include (or form) formaldehyde, which does the same thing in the soil that it did in your high school biology class when you used it to preserve specimens.
Chemical fertilizers are mostly nitrogen, phosphorus and potassium. Consistent applications of these nutrients at the expense of the dozens of others that are needed creates an imbalanced soil environment, not to mention the sewage sludge and toxic metals and all kinds of other garbage that are often included in the fertilizers as filler.
Most of the nitrogen and some of the phosphorus and potassium leaches into our waterways causing all kinds of problems to the greater environment. The manufacturers eventually started coating the chemical fertilizer with nutrients such as chemical sulfur to decrease this problem by making the fertilizer more “slow-release”.
This sounds like a great fix on the surface, except when heavy doses of sulfur combine with water to produce sulfuric acid and kill soil life.
Chemical Fertilizer Offenders?
While there are a couple of chemical fertilizers that may actually be useful once in a while, we must definitely stop using the traditional npk fertilizer products such as urea formaldehyde, triple superphosphate (0-46-0) and potassium chloride (0-0-60, including 40-50% chloride).
These are what make up many of the conventional nitrogen-phosphorus-potassium (N-P-K) fertilizers, such as 10-10-10, and they are extremely toxic.
There are many problematic chemical fertilizers effects from using these products. They are:
- harmful to soil life
- acidify the soil
- deplete the soil of nutrients
- cause compaction
- burn up organic matter
- pollute our water
- grow plants that invite predator damage
The chemical fertilizer industry would have us believe that plants prefer taking up their chemicals in ionic form, which means as molecules or elements with a positive or negative charge, such as calcium as C++ or sulfate as SO4--.
Plants certainly take up ionic chemicals, but they also take up complex organic molecules and prefer natural sources of vitamins and other substances to synthetic sources, just as our bodies do.
My Advice On Chemical Fertilizers
For the most part, if you don’t use pesticides, make sure you don’t use chemical fertilizers, either, especially the N-P-K brands from your local garden center. Stick to organic fertilizers, especially those I recommend on this site.
Now that these 2 articles are out of the way, I can get back to the fun stuff, which is what we should do instead as organic gardeners.
Update: About 2 1/2 years after I wrote this, I started selling the one chemical n-p-k fertilizer that I would consider okay to use. You can read about it here.