Bed Area Calculations

Well, it turns out gardening is also math! Who knew?
Here are some problems you might encounter when figuring how many bulbs to order. Use the chart below these area calculation examples to figure how many bulbs will be needed per square foot of flowerbed.
Good luck.


Rectangle

A rectangle is a parallelogram with four right angles.
The area of a rectangle is found
by multiplying the length (L) by the width (W).

Enter the length

Enter the width


answer in square feet

Example

Determine the area of a rectangle where
L = 100 ft. and W = 50 ft.
Area = (L)(W)
Area = (100 ft.) (50 ft.) = 5,000 sq. ft.

Circle

A circle is a closed curve of which every point on the edge of the curve is equidistant from a fixed point within the curve. The area of a circle is the radius squared (R2) multiplied by pi (3.14). The radius is equal to one-half the diameter of the circle.
3.14 is the numerical value for pi.

Enter the radius


answer in square feet

Pi's true value is
3.14159265358979

Example

Determine the area of a circle where
R = 20 ft.
Area = (3.14)(202 ft.) = 1,256 sq. ft.


Triangle

A triangle is a polygon with three sides.
The area of a triangle is one-half the base (B) multiplied by the height (H).

Enter length of base

Enter the height


answer in square feet

Example

Determine the area of a triangle where
B = 200 ft. and H = 100 ft.
Area = [(B)(H)] / 2
Area = [(200 ft.)(100 ft.)] / 2
Area = 10,000 sq. ft.


Oval

An oval has an elliptical or egg-like shape.
The area of an oval is the length (L) multiplied by the width (W), multiplied by 0.8.

Example

Determine the area of an oval where
W = 50 ft. and L = 100 ft.
Area = [(50 ft.)(100 ft.)] (0.8)
Area = 4,000 sq. ft.


Irregular Shapes

Here we divide a large irregular shape into a series of smaller units, equally spaced along a measured line (A-B). This method will determine the area to within 5 percent.

  1. Determine the length line. This is the longest axis of the shape, here shown as A to B.

  2. Mark the offset lines at right angles (90o) to line A-B.
    Choose how many offset lines to use so that they divide line A-B into equal segments and define regions for easy calculation. For example, if line A-B is 60 feet, a logical distance between offset lines would be 10 feet, since 60 divided by 10 equals 6, a whole number.
    If the flower bed is large, 300 feet or more, intervals of 10 to 30 yards should be used. If the shape of the area is uniform, then fewer offset lines are needed. However, if the shape of the area is irregular, more offset lines are needed. To ensure accuracy, use as many offset lines as possible.

  3. Measure the length of each offset line. These are measured from one edge of the area to the other.

  4. Add up the lengths of all offset lines and multiply by the distance between offset lines on line A-B.

The distance between points A and B is 60 feet
C = 10 feet
D = 15 feet
E = 20 feet
F = 25 feet
G = 15 feet

Example

  1. Determine the length line. Here A to B is 60 ft.
  2. Choose an offset distance. We made ours 10 ft.
  3. Measure the offset lines. In this example there are 5 - C, D, E, F and G
  4. Add the offset lines.Offset lines total is 85 ft.

The distance between offset lines is 10 ft.
Area = 85 ft. (10 ft.)
Area = 850 sq. ft.

Planting Chart: Number of bulbs per square foot

Tulips, standard 5 Tulips, wild 9-13
Daffodils, large 4-5 Daffodils, miniature 6-11
Hyacinthoides 5-6 Eranthis 20-24
Crocus 8-12 Allium Globemaster 1-2
Muscari 14-18 Fritillaria imperialis 1-2
Galanthus 16-18 Fritillaria meleagris 10-11
Scilla 15-16 Hyacinths 3-4
Chionodoxa 20-24 Anemone blanda 20-24
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