Gardeners Calculations
Mulching Calculations:
1 Cubic Yard Mulch = 27 Cubic Ft.
Covers 108 sq.ft. @ 3″ depth (New
Application) Covers 216 sq.ft. @ 1.5″ depth (Annual Top Dress)
1 – 3 Cubic Ft. Bag Mulch (9 bags = 1 Cubic Yard)
Covers 9 to 10 sq.ft. @ 3″ depth (New Application)
Covers 18 to 20 sq.ft. @ 1.5″ depth (Annual Top Dress)
1 Bale of Straw Covers 40 sq.ft. @ 3-4″ depth (New Application) Covers 60-80 sq.ft. @ 2″ depth (Top Dress)
1 Ton of 1/2″-1″ Pea Gravel (Assorted Types)
Covers approximately 100 sq.ft. per Ton at 2″ depth
1 Ton of 1″-2″ River Rock (Assorted Types)
Covers approximately 80 sq.ft. per Ton at 2″ depth
1 Ton of 2″-4″ River Rock (Assorted Types)
Covers approximately 60 sq.ft. per Ton at 2″ depth
Calculating Bed or Lawn Size:
Area Square Feet = Length of Area (x) Width of Area
Example: A 5 foot wide bed that’s 20 feet long
Length (5′) x Width (20′) = 100 square feet
Example: A 100 foot wide lawn that’s 50 feet long
Length (100′) x Width (50′) = 5,000 square feet
Calculating Soil or Material Coverage or Requirements:
Area Cubic Footage = Length of Area (x) Width of Area (x) Height of Area
Example: FAST ANSWER approximately 1 ton = 1 cubic yard COVERS 100 square feet @ 3″
How much soil do I need to raise or elevate a 10′ x 10′ square foot area by 3″
Length (10′) x Width (10′) x Height (.25′) = 25 cubic ft.
Answer is just a little under 1 cubic yard of soil which is 27 cubic ft. or 25 (1 cubic ft.) bags of bagged topsoil
Example:
I want to top dress an 20′ x 100′ area (2,000 square ft.) area with 1″ of soil.
How much soil do I need?
Width (20′) x Length (100′) x (.083′) = 166 cubic ft. of soil * Note – .083′ was derived from dividing inches 1″ x 12″ (1 ft.) = .083′
Answer: 166 cubic ft. of soil or (166 cubic ft. ÷ 27 cub.ft.) = 6.15 cubic yards soil
Measurement References & Guides:
1 Cubic | = | 27 Cubic Feet |
| 1 Cubic Foot | = | 12 Inches x 12 Inches |
| 1 Ton | = | 2,000 lbs. |
| 1 Square Yard | = | 9 Square Feet |
| 1 Acre | = | 43,560 Square Feet |
| 1 Teaspoon | = | 1/3 Tablespoon |
| 3 Teaspoons | = | 1 Tablespoon |
| 6 Teaspoons | = | 1 Ounce |
| 1 Tablespoon | = | 3 Teaspoons |
| 2 Tablespoons | = | 1 Ounce |
| 32 Tablespoons | = | 1 Pint |
| 64 Tablespoons | = | 1Quart |
| 1 Cup | = | 8 Ounces |
| 1 Pint | = | 16 Ounces (2 Cups) |
| 1 Quart | = | 32 Ounces (2 Pints) |
| 1 Gallon | = | 128 Ounces (4 Quarts) |
Calculating the amount of pesticide needed to treat a given area:
would you need to treat an area that measures 125 feet long by 90 feet wide.
First, calculate the area, or square footage, by multiplying the length of the area by the width:
125 feet X 90 feet = 11,250 square feet
You know you need 4 pounds to treat 1,000 square feet.
Again, set up ratios:
45,000 = 1,000 X
Solve for X by dividing each side of the equation by 1,000:
45,000/1,000 = X
∃ X = 45 pounds of active ingredient are needed to treat 11,250 square feet
EXAMPLE 2:
You will then need to determine how much of a given product you will need to deliver the needed amount of active ingredient. Building upon example
#1:
You know you need 45 pounds of active ingredient to treat the area calculated in problem #4. You have a 25G product (or 25% of every pound of product is active ingredient). How much of a 25G product (X = unknown) would you need to provide the 45 pounds of active ingredient needed to treat the area?
.25 pounds A.I./ 1 pounds of product= 45 pounds A.I./ X pounds of product ∃ (X) (.25) = (1) (45) ∃ .25 X = 45 ∃
.25 X/25 = 45/.25 ∃ X = 180 pounds of a 25G product are needed to treat 11,250 square feet.
[Or – to do it the really simple way – you know 1/4 of every pound of product is active ingredient. You can
just multiply 45 by 4 to arrive at the same answer of 180 pounds of product.]
Square Feet Mixing Useful Facts to Remember:
Often the label will give mixing instructions in terms of quantities of pesticide to be used per 1000 square feet as in turf treatments, or per acre as in commercial vegetables. In this case you will have to determine and adjust the amount of liquid your sprayer applies over a given area. This is called calibrating the equipment. When the equipment is calibrated you can add the proper amount of pesticide to give the recommended dosage per area. Calibration is described in Chapter XIX.
- 1 gallon of water weighs about 8.3 pounds.
- 100 gallons of water weigh about 830 pounds.
- 1 pound = 16 ounces = 453.6 grams.
- 1 pint = 16 fluid ounces = 473 milliliters.
- 1 quart = 32 fluid ounces = 946 milliliters = .946 liters.
- 1 pound wettable powder per 100 gallons = 1 tablespoon per gallon (approximately).
- 1 pint emulsifiable concentrate per 100 gallons = 1 teaspoon per gallon.