Food plots are a great way to attract wildlife to your property, improve wildlife nutrition, and improve hunting opportunities. One of the first and most important steps in creating a food plot is determining the size (acreage) of the plot accurately. Determining plot size is important because your rates for lime, fertilizer and seed are all based on this calculation. Not applying enough lime, fertilizer or seed can result in poor growth from your food plots. Applying too much of these things is a waste of money and can be detrimental to the land.
What is needed for measuring food plots?
In the United States area is measured in square feet for small sized parcels and in acres for larger ones. An acre is equal to 43,560 square feet. Food plots should be measured to the nearest one-tenth acre. Using multiplication and division, you can determine the area of your food plots with some simple field measurements of distance. The field measurements can be made easily with a tape measure, although you will probably want to have one that is at least 100 feet long or longer. If you plan to do a lot of this type of measuring, you may want to purchase a "string box" measuring device. To use it, you tie off the string and start walking. As the string pulls out of the box it turns a wheel that registers distance in feet on a meter. If you have a hunting range finder you can use this to measure the distance in yards and then convert that distance to feet (3 feet per yard). If you don't have any of these things you can always determine your pace and measure the distance that way. It is often easiest to find the areas of your plots by first dividing the plots into basic geometric shapes, and then measuring the areas of these shapes.
Measuring rectangular or square plots
The square foot area of any rectangular or square shaped plot is determined by first measuring its length and width in feet (Figure 1). Area is calculated by multiplying length by width. This can be expressed in a formula as: Area (square feet) = Length x Width
So, the area of the plot in Figure 1 is calculated as:
Area = 180' x 100' = 18,000 sq. ft.
Convert 18,000 square feet into acres by dividing by 43,560 square feet per acre:
Area = 18,000 sq. ft. ÷ 43,560 sq. ft. = 0.4 acres
Measuring an L-shaped plot
The easiest way to measure an L-shaped plot is to divide the plot into two smaller rectangles, find the area of each rectangle, and then add them together to get the total area of the plot (Figure 2). In this example, the larger rectangle measures 250 feet by 120 feet and the smaller rectangle is 100 feet by 60 feet.
Use the rectangle formula from above to find the area for each of the shapes:
Area = 250' x 120' = 30,000 sq. ft. Area = 100' x 600' = 6,000 sq. ft.
The sum of these two areas is 36,000 sq. ft. Dividing 36,000 sq. ft. by 43,560 sq. ft. per acre results in a total area of 0.8 acres for the entire plot.
Measuring irregular-shaped plots
The area of most irregular shaped plots can still be calculated using the basic equation of Area = Length x Width, you just need to calculate averages for these measurements. For the plot shown in Figure 3, measure one length of the plot (1227 feet) and then measure the width of the plot in three locations to find the average width: Average width = (431' + 422' + 460') ÷ 3 = 437 feet
Use the rectangle formula to find the area:
Area = 1227' x 437' = 536,199 sq. ft.
Dividing 536,199 sq. ft. by 43,560 sq. ft. per acre results in a total area of 12.3 acres.
Measuring triangular plots
To measure the area of a triangular plot, measure the two shortest sides of the triangle for the length and width measurements (Figure 4). Add these two numbers together and divide by two:
Area = (Length x Width) ÷ 2
So, the area of the plot in Figure 4 would be calculated as:
Area = (417' x 387') ÷ 2 = 161,379 sq. ft.
Dividing 161,379 sq. ft. by 43,560 sq. ft. per acre results in a total area of 3.7 acres.
That's it!
Now that you know how to measure the area of your plots, you will be able to order the right amounts of lime, fertilizer and seed. It won't be long before you will be reaping the benefits of your labor, with more and better quality wildlife on your property. The photgraphs below are from a hunting property in Tennessee and show a buck in a food plot and a nice doe harvested from a half-acre food plot.
