I wrote and posted the following to a gardening site several years ago. The original impetus was a contributor who for some reason thought that soluble synthetic fertilizers didn't contribute to soil life/structure and they were somehow detrimental to plant health, neither of which is true. Too, while organic soil amendments (aka organic fertilizers) have limited efficacy when soil temps are below 55* and when used for conventional container culture, something I touched on above.
In my gardens and beds, I adhere pretty strictly to the idea that on an ongoing basis you should use organic products/soil amendments that build the soil structure to minimize the need for soluble (read synthetic) fertilizers and nutrient supplements. That said, there are times you NEED individual nutrients to complete the assortment of essential nutrients plants take from the soil. If you're limited by a rigid 'no chemical' ideology, you either deal with the abnormal and sub-par growth or wait, while you hope adding more organic matter eventually solves all the issues. If you are NOT limited by rigid ideology, the issue is easily solved with a soil test and the addition of the appropriate nutrient(s) via a chemical compound like potash, various nitrates, phosphates, etc.
There are extremists at both ends of the organic vs. chemical approach to gardening. Some never think about the soil, believing it ok to keep adding chemicals to 'hopefully' produce growth. Others would never THINK of using a chemical and will chastise anyone who does. When it comes to my gardens and beds, I'm in the middle, but as noted I do lean quite heavily toward the organic side, though I stop short of telling anyone what they must do to be a good gardener.
Where container culture is the topic, soluble synthetic fertilizers get the nod from me - hands down. They are easier to use; we know exactly what nutrients your plants are getting and when they are getting them; delivery of nutrients does not depend on the activity of soil organisms whose populations vary in boom/bust cycles in containers; you're using a soluble product, not an organic soil amendment that has the potential to clog valuable macro-pores; you needn't worry about soil structure, because if you're smart you'll have built it into the medium before you planted in it ….. but let's save the container soil topic for another day.
I mentioned there are those at one end of the spectrum who would never lift a finger to improve their soil. Adding organic matter to their soils would be as foreign to them as adding exercise to their life's itinerary. On the other end, are those who stand ululating and hand-flapping (credit to Dan for that one) at the very thought of anyone using Miracle-Gro. From the plant's perspective, both extreme positions are ridiculous, and from my perspective, both extremes are unnecessarily self-limiting. The plant just wants to grow to it's genetic potential. To do that, it needs a full compliment of the nutrients plants take from the soil, and it doesn't care if they come from compost or Miracle-Gro.
Perhaps a more logical approach to plant nutrition might be to look at soluble synthetic fertilizers in the same way we look at IPM practices. Use the most naturally harmonious method/product we can to bring plant growth or yields into the acceptable range. I realize that in most cases, we can do this by adding more OM, but not always. Often too, time is a consideration. We may have someone who wants to plant immediately, in soil that is deficient in one or more nutrients. We probably shouldn't expect someone to forgo their own freedom of choice and wait two years or more while the soil is fortified/improved only via the addition of organic matter.
There is a technical difference between a fertilizer and a soil amendment, but even that point eventually becomes moot from a strictly nutritional perspective. Plants take up elements that are dissolved in the soil solution and in ionic form. What they take up are salts. The large molecules that make up hydrocarbon chains in organic fertilizers/soil amendments cannot be taken up by the plant unless the hydrocarbon chains are broken down into elemental/soluble form by soil organisms. At that point, the elements from soluble fertilizers are the same as the elements from organic sources, which is why the plant could care less. At the point in time where nutrients are assimilated, they are ALL soluble and in elemental form, regardless if they came from a dead fish, compost or a hose-end sprayer.
If we could only achieve happy healthy plants in a soil teaming with life, using only organic soil amendments and fertilizers, how do we explain hydroponics? ... no medium, or an entirely inorganic one, and only soluble sources of nutrients. At the very least it suggests there is a middle ground in which everyone can seek their comfort level. I've been growing perfectly healthy plants in containers in a medium whose only organic fraction is 1/3 or less pine or fir bark; the rest of the ingredients are large mineral particles like Turface and crushed granite. I've used ONLY soluble fertilizers in these soils, with the hundreds of pictures I've posted serving as concrete proof that happy, healthy plants can indeed be grown using only synthetic soluble fertilizers if the soil structure is favorable …… which leads me to the reason for writing this:
Colloquially, the term 'organic' formerly applied to things once living, but even some plastics contain carbon and are considered organic compounds as well. It really is misleading when we throw the word around w/o much consideration, but I admit to being guilty of it from time to time as well. Technically, urea, ureaformaldehyde, isobutylidene diurea, and crotonylidene diurea (forgive me if the spelling is slightly off) are all organic molecules, and actually do an extremely good job of feeding microbes, which reinforces the idea that synthetic fertilizers are getting framed for the microbial murder rap that should be hung on the effects of reduced OM in the soils. The microbial murder rap should be hung on the effects of reduced OM in the soils; purposely redundant so it couldn't be missed.
It's a vicious circle; mineral soils can support optimal plant growth (nutritionally speaking) only if enough young decaying matter is returned to the soil regularly and frequently. Prairies and forests are virtually self sustaining because all vegetative matter is recycled back into the soil. If we regularly mow and bale the grassland, or log off the forest, nutritional deficiencies are assured as a result of our removal of the OM that would have provided future nutrition - thus the tendency/need for us to adhere to the practice of replacing the lost nutrients with chemicals.
In our gardens/beds/lawns ..., we can add compost or other OM to replace the vegetative matter we remove and use or discard. For more than 20 years, I've used compost regularly in the gardens/beds, and apply fine pine bark mulch 2-3" thick, usually every other year. I have extremely healthy soil and rarely find it necessary to use anything synthetic.
You can find opinions all over the net that chemical fertilizers are laying waste to the landscape, and wiping out microbial populations faster than chocolate disappears from the candy dish in the family room. Are these opinions based on political views and a radical ideology, or warranted and based in fact?
In research by Texas A&M University, intensely managed (read 'managed using chemical fertilizers') sports fields with mostly a sand substrate showed no shortage of soil life. That is there were 10s of millions of bacteria, and 10s to 100s of thousands of fungi per cubic centimeter present in the heavily managed soils. Part of the study included measuring soil life in 11 inches (deep) of pure sand, with no organic amendments whatsoever, over which washed sod was placed. As the sod 'grew in', soil life populations increased almost immediately, 10-100 times .
Soil life populations just sort of hang loose, waiting for something they can digest. If they don't get it, they die and feed off each other. When organic matter is introduced into the soil, they break it down, and their numbers increase. When they've consumed the organic matter, they die and consume each other, but the base population remains, ready to spring into action the moment more organic matter becomes available.
What do fertilizers do? They make plants grow. Sure, extremely high concentrations of chemical fertilizer poured on the soil in volume might kill some microbes in the immediate area, but the o/a affect of chemical fertilizers is actually an increase in microbial populations through increased plant growth. You need only look to the fact that the rhizosphere (root zone) of plants is such a popular gathering place for soil biota to see increased plant mass promotes a marked increase in soil life. It's actually the continual 'taking' of OM from gardens, agricultural fields, lawns ... w/o replacing it that reduces or inhibits the communal activity of microbial populations. Even then, they're virtually never in short supply and are ever ready to bounce back ... if you just give them something to eat.
None of this addresses the hot button political, ideological issues too many wish to export from their own value set, other than the fact it points out the folly in occupying the margin's extremes. Again, I'm pretty pragmatic and results oriented, so I tend to approach this subject from a plant/soil perspective and leave the politics to the ideologues. My personal view is that in the o/a picture, a chemical fertilizer or nutrient supplement judiciously and responsibly applied to our gardens when it's found to be needed isn't the earth's end; and I prefer to use my own sense of right/wrong to set my course, rather than be told what I need to do to be a good, responsible student of husbandry.
That said, avoidance of unnecessary chemicals in the gardens/beds to the greatest degree I feel is reasonable, is still my normal MO. YMMV, but options are good, and I prefer to keep them open.
Al
