How to Measure Your Growing Area for a Greenhouse Cover?

Get ready for the upcoming growing season by assessing how much greenhouse cover you need. The best way to know how much plastic sheeting you’ll need is to measure your growing area. It’s less complicated than it sounds and will help you start growing sooner than later. To ensure you have what you need, don’t wait until the last minute to order. 

We’ve outlined how to measure your greenhouse cover with several tips and a few simple steps. See just how easy it is below.

Step 1: Grab Your Measuring Tools

Go to your growing area with your measuring tools. We suggest taking a measuring tape and a long piece of rope. You will need to collect four different measurements to calculate the amount of plastic sheeting that your greenhouse requires. 

Pro Tip: Bring a rope to help you measure round areas.

The easiest way to measure span C (see Figure 1) is to use a piece of rope or string. Go to one of the greenhouse hoops, toss the rope over the greenhouse, and lay the string on the hoop. Mark where the string touches the ground on both sides. Then, lay the string out on the ground and measure the distance between the marks on the rope.

Step 2: What Measurements to Take

The shape of a greenhouse is a long half-cylinder. You’ll need more than just height, width, and length to calculate your measurements. Now that you have the right measuring tools, refer to the graphic below to discover what areas you will measure before making your calculations.

Figure 1: Greenhouse Dimensions

Step 3: Calculate the Dimensions

This step will help you determine the size of film needed for the top and sides.

Step 3a: Determine Film Size

Multiply length A by span C.

Pro Tip: We recommend adding at least 2 feet to 4 feet to C dimension for attaching the cover to the greenhouse, or for securing a ballast (or anchor) to keep the film from blowing off.

Step 3b: Determine End Walls Film Size
Multiply measurements B and D.

Pro Tip: We recommend adding at least 1 foot to each measurement for attaching the cover to the greenhouse. 

Example Greenhouse Calculation

We’ve also included an example below to help you further understand how to calculate the area and adjust for additional length per our recommendations. Additionally, we’ve included a special note for greenhouse covers without solid end walls.

Sample Dimensions: A=50’, B=8’, C=38’, D=24’

• Step 3a: Calculate film size for top and sides: A x (C + 2 to 4 feet)

         Example: 50 x (38 + 4) = 50 x 42

• Step 3b: Calculate film size for end walls: (B+1) x (D+1)

         Example: (8 + 1) x (24 + 1) = 9 x 25

Special Note:
You will need a longer cover if your greenhouse does not have solid end walls. In this case, use the following formula to determine the length of the film needed. 

Add length A to height B, plus height B again, plus 2’ – 4’ to each B measurement. 

Example: 50 + 8 + 8 + 4 + 4 = 74’ 

This new number (74’) replaces the standard length measurement (A) when calculating film size for the top and sides.

Trusted by Growers, Builders, and Distributors

Americover is the smart source for plastic and polyethylene sheeting. Trusted by contractors and distributors across the construction and agriculture industries, our American-made products combine reliability with quality and innovation.

As an Americover client, you will receive the personalized support of a dedicated account manager to simplify the ordering process and ensure the best solution for each of your construction projects. Our friendly, knowledgeable staff is here to answer your questions and fulfill orders Monday-Friday from 6 a.m. to 6:30 p.m. Pacific Standard Time. If you would like to speak with a representative, call us at 760-388-6294 or contact us at sales@americover.com.