Lawn Care Facts
Today, we seem to get most of our lawn care information from TV commercials.
But, what are the facts?
- Organic fertilizers save time and money. They produce healthier lawns that require less mowing, watering and fertilizing.
- Plants have been evolving for millions of years living off decaying organic matter, AKA, organic fertilization.
- After several decades of chemical fertilizer use, we are only beginning to understand the problems these fertilizers cause.
- Lawn pesticides used (often unnecessarily) in 4-step programs have been found in all of our water systems, according to a recently released USGS study. Some of their known harmful effects are explained below.
Soils are a wonderful ecosystem. Soil organisms digest debris and recycle nutrients -- bring the nutrients to plant roots -- help keep plant pests and diseases under control -- and even produce plant growth hormones and anti-biotics. Each gram of healthy garden soil contains 1 billion bacteria, 20 million actinomycetes, 1 million fungi, 1 million protozoa, 1 thousand yeasts, and 100,000 algae.
Organic fertilizers bolster this natural ecosystem developed over millions of years.
- They nourish soil microbes and organisms like earthworms that improve the soil by recycling organic matter and aerating the soil naturally with their tunneling.
Chemical fertilizers are soil sterilizers.
- They drastically reduce the population of earthworms and soil microbes, and cause compacted soil and thatch buildup.
- Chemical fertilizers are very water soluble, and less than half of these fertilizers are absorbed by plants.
- The rest runs off into our groundwater and storm sewers, resulting in pollution of our water supply.
In Nature, plants gather their nutrients as they are slowly recycled by the decaying action of weather, worms, and soil microbes like bacteria and fungi.
In biologically active lawns, grass clippings and thatch decompose and are recycled as fertilizer -- so less fertilizer is needed. Organic fertilizers encourage this process. In contrast, chemical fertilizers are soil sterilants.
For example, thatch is only a problem in lawns that are heavily fertilized with chemical fertilizers, like those using 4-step programs. In these lawns, chemical changes in the soil kill off worms, bacteria and other organisms which decompose and recycle organic matter. A 7 year study at the University of Kentucky showed how chemical fertilizers kill of biological processes. The use of chemical fertilizers resulted in 66% fewer earthworms, even more damage to microbes, and a corresponding increase in thatch.
Organic fertilizers, especially composted products, also encourage natural microbes that help to control lawn diseases. These lawns show significant reduction in lawn diseases. Other studies have shown that chinch bugs will crawl over organically fertilized plots, to feed on plots fed only with chemical fertilizers.
Organic lawn fertilizers save time and money because less fertilizer, and fewer applications are required. Their slowly releasing nutrients are fully absorbed by plants. This creates slow and steady growth that maximizes energy production and energy storage in a thick root system that crowds out weeds.
In contrast, most chemical fertilizers are not fully absorbed. They leach into our water system creating a major pollution problem.
Beneficial insects, amphibians, and birds reduce pest populations, but their populations are severely damaged by pesticides and chemical fertilizers.
The Hazards of Lawn Care Products
A study by the Purdue School of Veterinary Medicine that links pesticide use to cancer surveyed 83 owners of Scottish terriers that had recently been diagnosed with bladder cancer. The report, published in the Journal of the American Veterinary Medicine Association, "found the cancer risk to be between four and seven times more likely in exposed animals."
The most comprehensive review of studies involving pesticide use - insecticides and weed killers - and health effects to date was done by the Ontario College of Family Physicians. Following are a few excerpts from the Systematic Review of Pesticide Human Health Effects, April 23, 2004
- “Exposure to all the commonly used pesticides — phenoxyherbicides, organophosphates, carbamates, and pyrethrins — has shown positive associations with adverse health effects. The literature does not support the concept that some pesticides are safer than others; it simply points to different health effects with different latency periods for the different classes…
- ...We have reported on many studies showing excess cancer risk in children exposed directly or indirectly to pesticides. These associated cancers include: brain cancer, kidney cancer in offspring of occupationally exposed men, and excess acute lymphocytic leukemia in children whose mothers used pesticides in homes and gardens during pregnancy...
- ...The elderly also have chronic neurological diseases that have been related to long-term pesticide exposure. These include Parkinson’s disease, amyotrophic lateral sclerosis, and Alzheimer’s disease. All these diseases are difficult to treat, which highlights the importance of prevention by reducing lifetime pesticide exposure…
- ...It is clear from the findings of leukemia studies that a positive association exists between pesticide exposure and leukemia. Of 16 leukemia studies included in this review, 14 show associations between pesticide exposure and leukemia, all but one with statistical significance…”
Researchers from the University of North Carolina and the National Cancer Institute (NCI) worked together in a study of over 600 children to determine what part local pesticide (herbicide) use plays in increasing the risk of having a late fetal death (after 5 months of pregnancy). Results of this study showed there was approximately 2-fold greater risk of stillbirth for mothers after a single pesticide exposure. “Exposure” was defined as an agricultural pesticide application that occurred within 1 mile of where the mother lived during weeks 3-8 of gestation.Weeks 3-8 of pregnancy is the critical period in which formation of organs and limbs are occurring. Birth defects are also associated with these exposures.
How Chemical Fertilizers Cause Plant Stress
Our turf grasses grow best in the cooler weather of spring and fall. During these months, grasses store energy in the form of carbohydrates just as animals store fat. This stored energy feeds lawns during the stressful days of summer and winter. Natural fertilizers, without excess chemical nitrogen, encourage slow, steady growth. This makes a thicker lawn requiring fewer mowings.
In contrast, spring and fall applications of chemical based, high nitrogen fertilizers over-stimulate grass resulting in rapid growth of grass blades. During this forced rapid growth, and therefore frequent cuttings, grasses actually consume stored carbohydrates when they should be storing them.
In summer, artificial fertilizers again over-stimulate our cool season turf grasses that are trying to go dormant to conserve energy. They are forced to consume carbohydrates faster than they can be replaced by the heat-stressed plants. Our lawn grasses are not active photosynthesizers in hot weather like warm-season plants such as crabgrass and dandelions. Therefore, chemical fertilizer applied in the summer give weeds an advantage over turf grasses.
Lawn Care Tips
- High quality organic fertilizers are the easiest, least expensive way to a thick, healthy lawn.
- The best way to control weeds is with a thick, healthy lawn that crowds out weeds before they get established.
- New Turf Fescue grasses are much tougher and require less maintenance.
- Fall is the most important time to fertilize, followed by spring.
- Water deeply and less frequently. This encourages roots to dig deeply and withstand drought better. Watering should be at least 1 inch per week, especially in summer. Because the lawn is dormant doesn’t mean it is dead!
- Grass kept at least 3 inches tall makes it harder for weeds, especially short creeping weeds like clover and crabgrass, to get established.
- The last cut in the fall should be shorter and raked off to prevent snow mold.
- Encouraging worms and microbes eliminates the need to dethatch and aerate
- Barespots seeded in the fall with grass seed will fill in and prevent crabgrass and other annual weeds from germinating in the spring.
- Lawn insects, including fleas can be best controlled with parasitic nematodes.
- Sharp mower blades make clean cuts that heal fast & minimize disease.
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