Chemical fertilizers can harm over time
By Leigh Jones
The Daily News
Published May 24, 2008
Advertisements for chemical fertilizer started airing on local television stations as soon as spring arrived.
Companies tempt gardeners to buy products that will get them rapid results, with promises to produce exponential growth, lush greenery and succulent fruits and vegetables.
But Bob Webster, a well-known gardening guru, radio host and horticulturist based in San Antonio, warns the short-term payoff is not worth the long-term cost of using chemicals.
Robing The Soil
Plants rely on bacteria in the soil to convert nutrients into a form that they can use, Webster said.
The microbes need an energy source to stay alive and do their work.
Chemical fertilizers do not include any energy source for the microbes, forcing the organisms to break down organic material in the soil to make use of the nutrients, he said.
Over time, using chemical fertilizers will rob the soil of virtually all of its organic material, making it hard-packed, crusted and incapable of holding water or oxygen, he said.
Organic fertilizers include micronutrients and an energy source to feed the microbes that convert the soil’s nutrients for the plant’s use, Webster said.
They also help reduce water use because they reduce the amount of water plants lose into the atmosphere, he said.
Growth Spurts
Gardeners usually love chemical fertilizers because they give fast results, but the growth they produce is not always the best, Webster said.
Rapid growth is usually week and susceptible to insects and disease, he said.
Chemical fertilizers also make plants thirsty, which leads to more water use, he said.
If chemical fertilizers aren’t used with lots of water, they will dehydrate the plant, a condition most often referred to as burning.
Organic fertilizers, on the other hand, contain nutrients that are released slowly into the soil, Webster said.
They do not promote rapid growth or excessive water consumption, he said.
The microbes need an energy source to stay alive and do their work.
Chemical fertilizers do not include any energy source for the microbes, forcing the organisms to break down organic material in the soil to make use of the nutrients, he said.
Over time, using chemical fertilizers will rob the soil of virtually all of its organic material, making it hard-packed, crusted and incapable of holding water or oxygen, he said.
Organic fertilizers include micronutrients and an energy source to feed the microbes that convert the soil’s nutrients for the plant’s use, Webster said.
They also help reduce water use because they reduce the amount of water plants lose into the atmosphere, he said.
Not To Worry
Although local extension agents recommend soil tests every few years to make sure the right products are used, Webster says the tests are only really necessary for farmers.
Most of the soil in the area contains similar levels of nitrogen, phosphorous and potassium, especially if it’s been treated with chemical fertilizer, he said.
Switching to an organic gardening program will begin repairing damage immediately and boost the micro-organisms in the soil that will help the plant absorb whatever nutrients is has available.
Webster also tells gardeners not to worry about the numbers usually written prominently on fertilizer bags.
“It’s not how much of the material is in there, it’s how much is available to the plants,” he said.