Lawns have three basic needs - fertilizer, water and sun. However, lawns will do better with rich fertile soil beneath them, something Colorado soil lacks. With water restrictions in the news this spring, I recommend top dressing in combination with an organic fertilizing program to create a soil teaming with life, nutrients and water.
Top dressing mix contains composted manure, organic matter and sandy loam. A thin layer of top dressing mix is spread evenly over the lawn and raked into aeration holes without smothering the grass. Composted manure provides nitrogen and microorganisms that will produce a thriving soil food web and continue to feed your grass a steady diet of nutrients while conditioning the soil. Organic matter will absorb water, break down clay and prevent the soil from drying out too quickly. Sandy loam also breaks down clay and improves the soils porosity which in turn prevents water runoff and allows better percolation of water to the root zone.
So why use organic fertilizer rather than synthetic fertilizer in combination with top dressing? Organic fertilizer conditions the soil and provides food for microbes and worms actively burrowing in your yard. Worms pull organic matter down into the soil feeding the soils food web. I have observed less worm activity on the surface following synthetic fertilizer applications. What is a worm going to do with a pellet of synthetic fertilizer? Microbes and worms benefit from a continuous supply of manure to breakdown into plant usable food.
Synthetic fertilizer provides nitrogen that feeds the lawn without adding the other benefits listed above for improving the soil. Less synthetic fertilizer is applied as compared to organic fertilizer because of its higher percentage of nitrogen. The amount of fertilizer to apply to lawns should achieve one pound of nitrogen per thousand square feet 3-5 times per year. A simple way to determine this is to divide the number one by the percentage of nitrogen written as a decimal and multiply that by the square footage of your lawn divided by a thousand. (To measure your lawn, go to www.findlotsize.com type in your address and click on the perimeter of each section of your lawn and add them up.)
For example, lets say a bag of synthetic fertilizer lists 20 percent nitrogen and you have a 2,500 square foot lawn. 1/.20 x 2,500/1,000 = 12.5 pounds of fertilizer should be applied to your yard each application.
For comparison, lets say a bag of organic fertilizer lists 8 percent nitrogen and you have a 2,500 square foot lawn. 1/.08 x 2,500/1,000 = 31.25 pounds of fertilizer should be applied to your yard each application.
Both of these calculations apply 1 pound of nitrogen per 1,000 square feet of lawn but organic fertilizer provides additional benefits for your soil. Both types of fertilizer will turn your lawn green but using organic fertilizer is truly “going green”. Good soil if full of life not just nitrogen.
Consider feeding your soil nutrient producing microbes and building it up with porosity increasing sandy loam and water absorbing organic matter. So many yards are hard as a rock, clumpy, and not growing very well as they get older. Water restrictions this season will only add to these problems. Change your thought process on how to do lawns. Use organic fertilizer and top dressing over the next couple seasons and you’ll get through water restrictions with a healthy beautiful lawn.