Science Experiment: Learning About Lawns

This science project is great for all ages.

Setting the Scene

Next time you drive through your neighborhood, a park or a pretty part of town, carefully observe the lawns and green spaces you pass.

Lawns are beautiful and elegant. They bring out the beauty of homes and gardens. They are calming and cool. People have been using lawns to beautify their homes for hundreds and hundreds of years.

We spend money on lawn services and cover our yards with fertilizers, herbicides, and pesticides to keep our lawns green and lush. Sometime when the sun is out, listen carefully; there is a good chance you will hear a lawnmower or leaf blower somewhere within earshot.

At least half of the water we use in northeast Florida goes onto our lawns. When the right amount of water is applied, the lawn stays healthy without wasting any water. All too often, though, people over water their lawns, so the excess goes to waste without offering any real value to the lawn.

Likewise, lawn chemicals such as fertilizers, pesticides, and herbicides can help keep lawns green and weeds and insects under control (though organic gardeners can argue convincingly that even they are unnecessary). Sadly, people often apply too much fertilizer and other chemical to their lawns. When they apply any more than is necessary to keep the lawn healthy, the excess becomes an environmental pollutant capable to contaminating waterways.

The good news is that lawns provide an excellent target for water conservation and environmental protection efforts. We do not need to do away with beautiful lawns to save water or sustain our environment. We just need to learn how to grow lawns that use water and other resources efficiently while maintaining their beauty.

In this science project, you can carry out a broad range of experiments to start becoming a lawn water expert.

Basic Information

For this science project, you will need a lawn to use. The larger the lawn, the more different experiments you can do simultaneously. In the best of circumstances, you have a lawn at home that your family will let you use. If you do not, talk to the facilities supervisor at your school to see if the school has a section of lawn you can use. Also, look around your neighborhood. Are there any unsightly lots that could use a little T.L.C. (Tender Loving Care) to beautify the neighborhood? If so, perhaps you could locate the owner and ask permission to use the lot for your science project and make it more attractive along the way. If none of these ideas work, try speaking with someone from your local parks department to see if there might be a plot of public land you could use.

Basic Design and Procedures

Using stakes and string, create a grid of square in the area where you can carry out your project. If possible, try making the squares at least three feet by three feet, though you can make them smaller if necessary. Ideally, you may be able to make them even larger. Each square in the grid will provide a space for a different experimental condition, so the more squares you can create, the more you will learn about growing lawns efficiently and responsibly. If you have a 30’ X 30’ lawn to work with, you can create 100 3’ X 3’ plots and set up 100 different experimental conditions!

Try to keep your entire experimental area as consistent as possible. Ideally, all parts of it will receive the same amount of sunlight and rain, and the soil beneath the grass will have been prepared in the same way.

Depending on the size of your experimental plot, you may want to water with a watering can because you will be able to control the exact quantities of water you apply to a specific section. If you have a large plot, divide it so plots needing similar amounts of water are next to each other.

Once you begin, measure and test every part of your lawn in a similar fashion.

Here is a list of experiments to conduct and observations to make:

  1. What type of grass works best in our climate?
    If possible without ruining a good lawn that is already in place, plant several different kinds of grass in your experimental plots. Use native or Florida-friendly grasses, such as St. Augustine, in some, and non-native species, such as Kentucky bluegrass, in others. Observe differences in the grasses under different experimental conditions. You may want to speak with a lawn expert at a nursery to get a good range of grasses that will perform in different conditions and exhibit different qualities.
  2. How much water do you apply per week?
    Water several different plots with different amounts of water each week, taking rainfall into account. At the low end, give the grass 1/4” or less each week, and at the high end, give it 2”. Keep a careful log of the appearance of the grass and the overall health of the grass. Every few weeks, cut out a small plug of grass and measure the length of the roots. The longer the roots, the healthier the grass. What is the minimum amount of water to apply to keep your grass healthy?
  3. What are the best times of day to water your lawn?
    Water one plot in the morning, one at midday, and one in the evening using identical amounts of water. Does one plot perform better than the others?
  4. What is the effect of shade on the health of your lawn?
    Build a low canopy from a tarpaulin or piece of canvas to provide shade. How does shade affect the quality and beauty of your lawn?
  5. What is the right amount of fertilizer to apply?
    Apply no fertilizer to one plot. In the other plots, experiment with different types and quantities of fertilizer. Ask a garden store which fertilizers work best on lawns. Your goal is to identify the minimum amount of fertilizer that will keep a lawn healthy. Start sparingly because you will find that you need to apply very little fertilizer. Most people apply too much, and it makes its way into local waters, sometimes creating a condition known as eutrophication.
  6. What is the optimal mowing length?
    Mow your plots at differing intervals and at varying lengths. Do certain grass heights or mowing schedules promote the rate of growth or the health of the lawn?
  7. What is the impact of mulch?
    Mulch helps the soil hold moisture. On some of your plots, leave the cuttings (thatch) from mowing, and on others, remove it. Measure the difference in rates at which the soil dries and requires more water.
  8. Organic versus non-organic.
    Organic gardeners shun the use of any chemical fertilizers, herbicides, or pesticides, and they often encourage the use of native plants in yards and landscapes. Consult with a local organic gardener, and practice organic and non-organic techniques in your plots. Observe, define and describe the differences in growing techniques, fertilization, bug and pest control, and watering between organic and non-organic gardening techniques.

Reporting Your Results

Make drawings, diagrams, and charts of your experimental results.

Create a lawn care manual for the homeowners in your neighborhood. Perhaps you could even publish it and sell it to the families of your school as a PTA fundraiser.

Report on the environmental effects of overwatering, overfertilizing, and the overapplication of chemicals.

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