Caterpillar Tunnel vs. High Tunnel | What’s the difference?

by Becky

It can be confusing to figure out what the difference is between a caterpillar tunnel vs. high tunnel. We have assembled and used both, so it is my hope that this helps anyone wondering why you would want either one or the other. 

Haven High Tunnel

What is a Caterpillar Tunnel?

A caterpillar tunnel gets its name from looking like a caterpillar with different segments. Its construction is similar to a low tunnel, the main difference is a caterpillar tunnel is a tunnel that is tall enough to walk under, usually between 7 and 10 feet tall.

Caterpillar tunnel

Assembly and Construction

It is constructed by pounding rebar in the ground. On each piece of rebar an anchor plate is added, then the metal bows slide over the rebar. 

Each of the metal bows is connected at the top with a long metal bar, known as a center perlin, this creates stability. 

Then the entire tunnel is covered with plastic and attached with wiggle wire to the end hoops. And finally, rope is added and attached to the anchor plates so the plastic along the length of the tunnel doesn’t billow in the wind. 

Additional features that can be added on are wind bracing, a lift kit to make it taller, and end walls to enclose the entire thing.

Because a caterpillar tunnel slips over rebar, it’s a little less permanent, and could be moved to another area of the garden because setup is fairly quick. 

Pros and Cons of a Caterpillar Tunnel

Pros:

  • Easy and fast set up
  • Offers covered growing space for an inexpensive price per square foot.
  • Not permanent

Cons

  • Low structural stability, hoops aren’t attached to rebar and it is less stable in weather events
  • Sides are manually lifted for ventilation
  • Not as airtight, more susceptible to cold if plastic is not weighted down with sandbags

What is a High Tunnel?

Sustainable Agriculture and Research Education defines a high tunnel as:

High tunnels, or hoop houses, are simple greenhouse-like structures over bare ground, without the elaborate heating and cooling systems of a greenhouse. They rely primarily on passive solar heating and passive ventilation. High tunnels generally have steel pipe frames set into the ground and are covered with one or two layers of greenhouse-grade plastic.

It sounds quite similar to a caterpillar tunnel, but there are some key differences. 

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Assembly and Construction

A high tunnel is constructed by hammering in ground posts. The ground posts are more structurally stable than the rebar used in caterpillar tunnels. 

Next, baseboards are attached to the ground posts. This adds another layer of structural stability along with a more weatherproof base. 

Metal hoops slide onto the ground posts and are screwed together. A center perlin is attached and then hip boards add even more structural stability.

When the plastic is added on it is laid over the top and attached to the hip boards/ double c channel with wiggle wire, in addition to the ends.

This makes it so the plastic over the entire top of the structure is secure and will not move a lot with the wind.

The plastic below the hip board is loose to allow ventilation with a roll up bar and either an automatic crank or hand crank. 

High Tunnel Pros and Cons

Pros:

  • Very stable and structurally sound, it is less likely to collapse or fail during a significant weather event. 
  • Easy to ventilate with a crank and roll up bar.
  • Better sealed for cold weather

Cons:

  • Takes longer to set up than a caterpillar tunnel
  • More permanent, not easily moved
  • All the additional components for structural stability make it more expensive. 

Caterpillar Tunnel vs. High TunnelWhat is the Difference?

The main differences between a caterpillar tunnel and high tunnel are structural stability, added components and therefore added cost, and how weather proof it is.

See the table below for specific comparisons:

Gothic vs. Classic Style Tunnel

Both the caterpillar tunnel and the high tunnel come in either gothic style or classic style. Either style can be used depending on your preference and needs.

Gothic style is peaked at the top. Classic is a rounded half circle shape.

The gothic style of tunnel is better for areas that receive snowfall. The peaked top allows the snow to shed off easily. It is slightly more expensive, but worth it if you need it.

The classic style is cheaper and can perform better in areas of high winds.

DIY Caterpillar tunnel and High Tunnel vs. Buying a Kit

A caterpillar tunnel and high tunnel can be sourced by an individual piece by piece or a kit can be purchased. 

Believe it or not, a DIY tunnel often ends up costing more than buying a kit. Especially if you compare exact components. Source 

We purchased our caterpillar tunnel HERE and our high tunnel HERE. In my opinion it’s the best quality on the market and everything is included down to string and screws. 

Full disclosure, I am an affiliate and make a small commission on anything purchased at no additional cost to you. If you end up buying a tunnel whether now or later, it would mean a lot to me if you use this link, it helps so much! The reason I’m an affiliate is because this is the BEST company out there for tunnels, hands down. 

We’ve done enough projects to know that you almost always need to run to the store to get more of something or something you forgot, usually multiple times. 

It saves an incredible amount of time and effort having the kit. I am so happy we went that route.

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