A caterpillar tunnel is a great form of season extension for your market farm. 

If you’re like us and are on a bootstrap budget this season, caterpillar tunnels just may be your best friend for lengthening your growing season and providing warmth to those heat-loving plants you will be growing.

Since I don’t have a lot of experience with caterpillar tunnels yet, I will be referring to J.M. Fortier’s expertise with regard to the building and price of a caterpillar tunnel.

What Is A Caterpillar Tunnel?

A caterpillar tunnel is an inexpensive and simpler version of a hoophouse. It provides shelter, warmth, and airflow to the growing environment.

A handy feature of caterpillar tunnels is that they are moveable.

The structure is easy to set up and take down so they can be moved over established crops at different times of the season. 

How Do You Make Caterpillar Tunnels?

A caterpillar tunnel can be built using a number of techniques and materials.

A basic tunnel requires only PVC pipes, rebar, and rope.

J.M. Fortier from the market gardener built his tunnel by using 1 ½ “ PVC piping made up into 20 ft. lengths using two pieces joined together firmly with glue.

The hoops were spaced every 10ft. And anchored to the ground on 24” rebar (⅝” diameter) driven halfway into the soil. 

He tied a rope from hoop to hoop to form a purlin (horizontal beam) that runs the length of the tunnel.

The rope was then firmly stretched to give rigidity to the tunnel and tied to stakes at both ends.

The covering (he used old greenhouse plastic) was then pulled over the tunnel and held to the ground by sandbags.

To keep the plastic from flying away on windy days, he stretched the rope over it midway between each arch and tied the rope down to stakes in the ground, giving the tunnel its caterpillar-like appearance.

Ventilation is controlled by simply rolling up the entire side of the tunnel, keeping it in place by hooks attached to every other arch.

Now that doesn’t sound too bad, does it?

How Much Do Caterpillar Tunnels Cost To Make?

To make the caterpillar tunnel described above, in 2005 it cost J.M. $400, not including the greenhouse plastic.

This covered an area of 10 X 100ft, providing cover for 6 beds for an investment of $0.33 per square foot.

Advantages of Using  Caterpillar Tunnels

There are many advantages of using  caterpillar tunnels, they are:

• Inexpensive
• Relatively easy to DIY
• Movable

Disadvantages of Using Caterpillar Tunnels

The only real downside of caterpillar tunnels is that they are a low structure, providing little clearance to properly work in an upright position.

Entering and exiting the tunnel also involves a lot of bending.

Overall, the advantages well supersede the disadvantages, at least in my opinion.  

We will be making our own caterpillar tunnel this spring, so you can bet that we will be documenting the process and informing you of our experience.

Do you use caterpillar tunnels as season extensions? Let us know in the comments below.

Stay Local,

Kathy & Jon

your friendly neighbourhood growers