University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Math and the Yard & Garden

February 15, 2001

While you may not think of it much, mathematics is an important part of yard and garden care. Planning for planting, fertilizing, mulching, and pest control all involve some math, yet it is often overlooked.

For example, do you know the area of a planting bed, vegetable garden, or lawn in your yard? Once these figures are known, record them so they are readily available when needed. Individual planting beds or garden areas can simply be measured and the square footage calculated. For example, area of a garden measuring 20 feet by 25 feet would be 20 times 25, or 500 square feet.

Some basic formulas are needed to make these calculations. The area of a square or rectangle, as just calculated above, is simply length times width. Calculate the area of a triangle by multiplying base times height and dividing by 2. For a circle, square the diameter (take it times itself), multiply by 3.14, and then divide by 4. Remember the diameter is the distance all the way across the circle, as compared to radius, which is from the center to the edge.
Larger areas, such as for lawns, can be calculated different ways. One way is to take the entire size of the lot and then subtract everything that is not lawn area. Keep in mind an acre is 43,560 square feet. If your lot is 1/2 acre, divide by 2; 1/4 acre divide by 4, etc. to come up with an overall base square footage. Then subtract the area of the house, drive, deck, and gardens.

Another way would be to break up the property into separate lawn sections and calculate the square footage of each.

Why are these area figures needed? If planning a vegetable garden, space available needs to be known before seeds or transplants are ordered. Likewise with flowers, groundcovers, or grass seed. Proper spacing and seeding rates are important in the success of a planting.

Planting areas are also needed for adding soil amendments and fertilizer applications, as well as pesticides. For garden areas, rates are typically given as pounds of material per 100 square feet of garden area. For lawns, rates are usually expressed as pounds of material per 1,000 square feet. So before fertilizer can be applied, for example, the area of the lawn or garden needs to be known. For field crops, these rates are usually given on a per acre basis.
As the weather allows, take a stroll around your yard and make the necessary measurements soon!

 

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