There’s a growing philosophical debate among gardeners between those who advocate synthetic chemical fertilizer approaches and those who prefer natural organic methods. What often gets lost in this debate are the scientific facts.

Both approaches offer advantages and disadvantages and frequently, master gardeners use both. Let’s focus on the pros and cons of synthetic chemical methods compared to natural organic methods in the following areas:

Hopefully, this will help you develop your own philosophy of caring for the plants you grow. "Philosophy" is the operative word here. The choice to use salt-based chemical fertilizers or carbon-based organic fertilizers, or both, really depends on whether you’re trying to feed the plant only, or feed both the soil and the plant.

That’s the fundamental distinction between conventional chemical methods and more traditional natural methods of growing and gardening, at least when it comes to fertilization and nutrition.

On the one hand you have the conventional chemical gardener who says: "The plant doesn’t know the difference between nitrogen whose origin was a naturally-occurring material and nitrogen synthesized in a chemical fertilizer factory. Therefore, I’m going to feed my plants with the cheapest form of nitrogen I can find."

On the other hand you have the traditional organic gardener who says: "I will take care of the soil and the soil will take care of my plants. A healthy soil will provide all the nitrogen and other nutrients my plants need."

It’s next to impossible to get an "apples to apples" comparison between synthetic chemical salt-based fertilizers and carbon-based organic fertilizers. In general, if your only criterion is how much the fertilizer costs per unit of nitrogen, the salt-based synthetic fertilizer will almost always win. If, on the other hand, you factor in the value of the additional benefits claimed for organic fertilizers, such as healthier plants and improved resistance to insect pests and diseases, organic fertilizers might be more economical than the synthetic.

And when you consider the environmental impact of each, the balance tilts even further in favor of organics.

All Organics Are Not Created Equal

And of course if you are growing vegetables, you want the healthiest additives to your soil and plants. For example, you probably want to avoid bovine bone meal, biosolids, and animal manures. On the other hand, you probably do want to include things like kelp meal and seaweed extract.

Studies of cattle grazing on grasses sprayed with seaweed extract have shown increased levels of disease resistance, and increased levels of antioxidants in their blood.

Organically grown vegetables have been found to be more nutrient rich. Most people feel they taste a great deal better, too.

Better, Faster, Cheaper…You Can Have Any Two Out of Three

If it’s better and faster, it won’t be cheaper. If it’s faster and cheaper, it won’t be better. And if it’s cheaper and better, it won’t be faster. Advocates of organic fertilizers would say that their approach falls into this latter category. They would concede that while their approach is not faster in the short run, it’s better and cheaper in the long run compared to salt-based synthetic chemical fertilizers

Soil Microorganisms Eat At the First Table. Plants Eat At the Second Table.

This, in a nutshell, is the underlying premise of traditional organic-based growing and gardening. If you focus on building and maintaining a healthy and flourishing "living" soil with high levels of beneficial microorganisms, the growing medium itself will provide what plants need.

The key to this system is to provide a continuous supply of various sources of carbon (that’s what the organics provide) to the microorganisms in the soil. Initially, the microorganisms compete with plants for the nitrogen to fuel their energy needs to digest the carbon sources. However, as the microorganism population reaches "critical mass," it makes excess nitrogen available to the plants growing in the soil. This "recycling system" then provides all of the plant’s nutrient (and many other) needs on a sustainable basis…as long as there is a continuing supply of diverse carbon sources.

meaning, that if you have the right food sources (carbon) you’ll get the right microorganisms. And that’s central to the major benefits associated with organic-based fertilization.

The Intelligent Use of Organics…The Key to Integrated Pest Management (IPM)

One thing that all growers and gardeners agree upon is this: the most important single step in plant protection is plant health. Plant pests and predators attack the weak first. Therefore, creating the healthiest possible habitat and host plant community is the cornerstone of intelligent integrated pest management. And while both salt-based synthetic chemical fertilizers and carbon-based organic fertilizers provide the mineral nutrients necessary for plant growth, only the organic fertilizers can provide the carbon necessary for healthy soil systems. A well-balanced carbon-based organic fertilizer program can provide the food source necessary to "jump start" and sustain a healthy and diverse population of soil microorganisms.

For example, there is abundant university research that confirms that plants growing in soils with higher microbial populations have lower disease incidence. While the modes of action are not completely understood, it is theorized that higher levels of beneficial microorganisms that are antagonistic to pathogenic microorganisms serve as a natural defense system against disease.

As you choose which fertilizers to use this season, consider your gardening philosophy. If you’re thinking about your garden for more than one year at a time, it makes sense to "go organic" because the benefits and results are cumulative. Keep in mind the importance of soil microbiology. Remember to feed the soil and you will have abundantly healthy and beautiful gardens. And you’ll favorably impact the environment as well.

Bill Middleton

President