I believe a leaf of
Grass is no less
Than the journey-work
Of the stars
-Walt Whitman
The first thing I want to say is what many of us forget…that grass (as in lawns) is made up of thousands, if not hundreds of thousands of plants. And plants are the only organisms on earth that produce their own food through photosynthesis. Plants take in energy to make food. We humans, on the other hand, take in food to make energy.
But there is more to caring for lawns than watching the grass grow. Water, air, bacteria, protozoans, mycorrhizal fungi, microscopic mites, and many other living organisms are necessary for a lush green lawn.
The soil under the lawn is infinitely more important
I have had the fortune (or misfortune) of visiting a great many lawns, assessing damage from fungus, bacterial, and pests. One thing I found constant was that virtually all the lawns I visited and diagnosed were growing out of hardpan soil. The roots of the turf were struggling to get more than an inch deep into the soil.
And that meant the turf plants could not get the nutrients they needed to grow strong and healthy. Unhealthy grass plants are subject to all types of diseases. Large patch, take-all patch, gray leafspot, summer patch, dollar spot and a whole range of other destructive and costly situations.
No amount of fertilizer, fungicide, pesticide or herbicide can work very well, especially if it cannot penetrate the soil and is washed off the hardpan by rain or irrigation.
Solutions
First, we need to get nutrients down below that crust of soil that is preventing the grass roots from spreading deeply into the soil. Plus we need to make the soil loose enough for water and other nutrients to sink down into the soil.
Water
Water from rain and irrigation needs to enter the soil and provide water to the roots of the plant and to the microbes that live in the soil and provide nutrients to the turf. The water also helps dissolve some nutrients. Not too much water, though. According to research, lawns do not need more than an inch of water a week, and only during growing season. And that includes rainwater.
Bacteria
Bacteria in the soil dissolve most of the nutrients and fertilizer. These bacteria are really important to the health of the soil, and the health of the individual turf plants that ae growing in your lawn. But bacteria cannot live in compacted soil.
Mycorrhizal fungi
Mycorrhizal fungi extract nutrients from bacteria and soil and carry them to the roots of plants. In return, plants give the fungi carbohydrates. These types of fungi have deep relationships with the total health of plants and soil.
Chemical Fertilizers
Excessive Use of chemical fertilizers (and chemical pesticides, herbicides, and fungicides) leads to serious soil degradation, nitrogen leaching, soil compaction, reduction of soil organic matter and loss of soil carbon.
