- by Grey County Master Gardeners

A gardening pal recently asked me about the application of Triple-19 agricultural fertilizer to residential garden beds in the late winter, right on top of the snow, in the hope of lush growth come summer.

Now, I try to be sensitive to sources of advice being dispensed but I realized it was time to have the talk about synthetic fertilizers. I still own a gardening book from the 1960s that recommends the use of malathion in the garden. I can remember the nauseating smell of the active ingredient, DDT, in Fly-Tox, the popular insecticide that was still in use when I was a kid. We all know the payload that came with those products. In the ensuing decades much has changed, and when I hear about a new product I have learned to ask, “What else does it do?” There’s a dark side to chemical fertilizers, and I would continue to recommend against their use for a host of reasons.

First of all, when applied to cool, wet ground, as much as 16% of the active ingredients will dissipate into thin air, adding even more carbon and nitrogen to the atmosphere says a study conducted by Montana State University. I’m certainly not about to toss 16 bucks out of a hundred to the wind. Money aside, many of the ingredients that remain will kill off the beneficial soil microorganisms that convert dead animal and plant material into nutrient-rich organic matter. This disrupts the symbiotic cycle of growth and decay that is the mainstay of soil health. Without that cycle, you don’t have soil; you only have dirt.

Furthermore, synthetic fertilizers leach their compounds into groundwater, leading to water pollution. Among other disruptions, toxic algae blooms eventually lead to poor oxygenation of the water and to the death of aquatic life forms. We have long used low-phosphate and phosphate-free detergents for our laundry in order to protect the environment yet many of us haven’t yet made the connection between chemical fertilizers and potential harm.

Synthetic fertilizers also increase the nitrate levels of the soil. Plants grown in such soil, upon consumption, are known to convert to toxic nitrites during digestion which can wreak havoc on human health. Most of us who eat homegrown do so to optimize nutrition and to avoid consuming foods grown in soil that has an unhealthy nutrient profile.

Synthetic fertilizers damage the microbiome of soil in the long term. Alas, restricting their application to flowerbeds doesn’t mean the leaching and run-off won’t make its way into the soil where you are growing edibles. Plants that grow in overly fertilized soil are often deficient in iron, zinc, carotene, vitamin C, copper and protein. Of course, the plants in your flower garden, your perennials and shrubs in particular, would be equally susceptible to such deficiencies.

Clay soils, such as we have here in Grey County, are already rich nutrient banks. Clay, by its nature, holds a lot of the minerals that plants seek and rarely needs us to add more. Clay is also very prone to compaction. Synthetic fertilizers contain acidic ingredients which, over time, can dissolve and cause even more compaction of the soil. Compacted soil’s inability to drain well can lead to root rot and the actual drowning of the microscopic organisms that make soil a thriving community of microscopic living creatures. Once dried out, compacted soil can have the opposite problem of not absorbing water thus desiccating and killing the very same beneficial organisms.

What our clay soil does need from us is enough organic matter to increase the flow of moisture and air; to lighten it and make it more friable; to help it absorb and store carbon and nitrogen. The organic matter gardeners supply to the soil helps support the population of soil microorganisms that play a huge role in the processes that enable plants to absorb nutrients from the soil. You provide the missing ingredients with the initial incorporation of compost into new garden beds and then frequent surface applications of compost thereafter. You protect this investment by not disturbing the soil and by keeping the ground protected with a cover of plants and suitable organic mulch mimicking a forest floor.

Please join us for our third Free Eco Responsible Gardener seminar. To register go to greycountymastergardeners.com.

Seminar 3: If Only Trees Could Talk presented by Jen Llewelyn, Sunday April 11, 2021 at 1 pm.