People love their lawns. Having a nice thick, lush, green lawn is almost like a badge of honor to some. It’s May in the Northeast and everywhere I go I see people applying fertilizer to their lawns. We all do it, right? Ask yourself this question first. Why? Sure we’re all told we should fertilize the lawn in the spring to help invigorate the grass after a long hard winter and to apply fertilizer in autumn to help prepare the grass for the long hard winter. Some of us even subscribe to the 5 step year round fertilizer programs that are pushed by fertilizer companies, but is it really necessary? The short answer is probably not. Treating your lawn with fertilizer without having a soil test performed is like taking blood pressure medicine without checking your blood pressure first. You don’t know if you actually need it or not.
Billions of dollars are spent in the U.S. each year on fertilizer. Millions of pounds of synthetic pesticides are applied to lawns in the U.S. each year. This is all in an effort to keep the grass looking full, green and weed free. Some of the fertilizers and pesticides applied to landscapes each year is lost due to rain and precipitation. They’re carried through storm drains or down slopes or through the ground water to nearby waterways (rivers, streams, oceans, ponds, etc…). In 2001 a study conducted by USDA showed 80% of synthetic fertilizer is wasted/lost (by run off, leaching through the soil, etc…). That’s like paying someone 100% of the cost to perform a job, but only getting 20% of the job done in return. It just doesn’t make a lot of sense.
In waterbodies such as ponds or slow moving streams, the excess nitrogen in the water can produce algae blooms. The algae feed off the nitrogen and in the process deplete the amount of oxygen that’s available in the water to other plant and animal life. This can lead to the death of fish and other organisms. The chemicals in pesticides are harmful to wildlife as well.
Synthetic nitrogen and pesticides can kill and harm a soil’s beneficial microorganisms. By using these products consistently, it becomes the equivalent of placing your lawn on drugs. The soil that supports your lawn will lose it’s natural ability to support itself and will become nearly dependent on these additives each year. I’ve seen people who’ve made an attempt to use organic treatments on their lawns after using synthetic fertilizers and pesticides on their lawns and landscapes for years. They don’t see the instant results and begin to doubt the process. What they don’t understand is that the soil that supports the lawn is basically going through a “rehabilitation” process. It takes time for the natural organisms and processes to return to the soil.
Soils, if treated properly, have the ability to provide a beneficial underground environment for the lawn and microorganisms. Many of these organisms break down organic matter and provide the nutrients and symbiotic relationships that are beneficial to plant life (Trees, shrubs, grasses, etc…). Healthy soils are typically full of bacteria, fungi, and nematodes. They also tend to have good top soil that’s a minimum of 6″ deep(8″ preferable) and a 4 – 6% organic matter content. These “healthy soils” can provide an underground environment that assists in keeping an established lawn full, green, and weed free without the need to fertilize and treat it for pests all the time.
Now, I’m not saying everyone should run out and have a soil test done every year, but if you have one done every two or 3 years you can get a good feel for what your lawn really needs and how it and the soil may be evolving overtime. Soil tests are full of information that can help you to treat your lawn and other landscape vegetation in the appropriate manner. Soil tests can show the PH level, nutrient levels, soil texture, organic matter content, and more. Soil testing performed by a lab (like the one at UMASS-Amherst) will also give you recommendations on how to improve the soil based on the results of the testing. One main reason soil testing is important is because it can help you to see what nutrients or amendment it really needs to be healthy and even more importantly…what it doesn’t need.