Product information


Caterpillar Tunnel Max

As low as $287.83/mo.

Product options

Front End Wall

The Max works best with an end wall. Configure your front end wall below.

Back end wall

The Max works best with an end wall. Configure your back end wall below.

Free shipping to contiguous USA.*
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Level up your Tunnel Growing!

The new Caterpillar Tunnel Max brings the ben­e­fits of large green­house pro­duc­tion to your farm while still coming in an easy-to-assem­ble and afford­able kit! The new 21-ft wide Caterpillar Tunnel Max provides 50% more growing space than a standard 14-wide Caterpillar Tunnel allowing for a more efficient use of your growing space by having faster access to more beds under one roof. You’ll even gain better access to the far edges of your tunnel with increased side-wall height. Available in both Gothic and Classic styles.

Quick Assembly
Quick Assembly
As low as $2.71/sq. ft.
As low as $2.71/sq. ft.
NRCS Eligible
NRCS Eligible
FREE SHIPPING to Contiguous USA!
FREE SHIPPING to Contiguous USA!


Increased strength to withstand the elements

Every Caterpillar Tunnel Max is made with larger 1 5/8" diameter bows (up from 1 3/8") in industry-leading 14-gauge thickness. The new Earth Lock Anchor Plates at the corners are second in strength only to ground posts in concrete! Plus with the addition of a second purlin and a third wind bracing section on each corner, this tunnel is made to withstand the elements!

Maximize your Investment

Two Caterpillar Tunnel Max tunnels will cover the same growing space as three 14-ft wide Caterpillar Tunnels. This allows you to reduce the number of end walls needed and effort to ventilate the same amount of growing space by 33%.

All-season growing

Year-Round Crop Protection

Caterpillar Tunnels are often viewed pri­mar­i­ly as a sea­son exten­sion tool, but that’s real­ly only half of the sto­ry. Covered grow­ing space pro­vides year-round pro­tec­tion for your plants from things like rain, pests, frost, heat (when using shade cloth), wind, and even from dirt being splashed onto your plants in heavy down­pours. (Image shown with 14-ft wide Caterpillar Tunnel)

Rain Protection
Rain Protection
Pest Protection
Pest Protection
Frost Protection
Frost Protection
Heat Protection
Heat Protection
Wind Protection
Wind Protection
Cleaner Crops
Cleaner Crops

Why choose Caterpillar Tunnel Max?

More growing space under one roof

Stronger metal + strength upgrades

Year-round crop protection

Irrigate on YOUR sched­ule

Quick and easy assembly

Step-by-step instruc­tions with pic­tures + video

NRCS grant eligible

Cheaper than DIY

Comes with all parts need­ed!

FREE SHIPPING on all tun­nels! (to contiguous USA)

5 out of 5 stars

If you are looking to maximizing your growing space on your farm, then the Caterpillar Tunnel Max is your answer. Designed with efficiency and productivity in mind, this new offering from Farmers Friend enables you to grow more produce on a small plot than any caterpillar tunnel on the market right now.

Ray Tyler
Rose Creek Farm

Customizable Length

All-New Length Options

We're thrilled to offer the Caterpillar Tunnel Max in an expansive range of length options! Whether you're working with a compact 30-ft plot or stretching out to a sprawling 110-ft, there’s a perfect Caterpillar Tunnel Max for your farm.

50-ft / 6-10 hrs assembly time
50-ft / 6-10 hrs assembly time
100-ft / 8-14 hr assembly time
100-ft / 8-14 hr assembly time


High profitability. Low cost. Free delivery.*

The Caterpillar Tunnel Max is one of the most cost-effec­tive options on the mar­ket — even when com­pared to DIY kits. Plus get FREE ship­ping right to your door on any tunnel size — regard­less of how many you order! Your plants will thank you.

*Free ship­ping to contiguous USA. Discounted ship­ping to Canada.

Assembly & Mobility

Easy up. Easy down.

With our in-depth instal­la­tion video and includ­ed step-by-step instruc­tion guide, this will be the eas­i­est tun­nel you’ve ever built. Two peo­ple can ful­ly assem­ble a 21′ × 30′ Caterpillar Tunnel Max in as few as 6 hours. Our Caterpillar Tunnel Max kits are movable by design to adapt to your farm's needs—including easy transport to a new farm location if necessary.

Frequently Asked Questions

Is there a 4-ft bow spacing option?

Not exactly... The Caterpillar Tunnel Max is only sold in 5-ft spacing configurations, but if you really want to have a 4-ft bow spacing tunnel, you can simply buy a slightly longer tunnel and install your bows closer together, except for the first 3 and last 3 bows. This will allow for your wind bracing to fit correctly. For example, if you want a 48-ft tunnel with 4-ft bow spacing, order a 60-ft tunnel with 5-ft bow spacing and install the bows closer together.

What end walls work with the Caterpillar Tunnel Max?

We have designed new 21-ft wide versions of the Framed Double Zipper End Wall and the DIY End Wall to for the Caterpillar Tunnel Max.

Will there be a pro version like the 14-ft and 16-ft wide Caterpillar Tunnels?

No. The pro package for our standard Caterpillar Tunnels adds two main features: a Lift Kit, and Cross Bars. The Caterpillar Tunnel Max is tall enough already that no Lift Kit is needed, and cross bars are not an option for the Max.

Can I add roll up sides?

We don't currently sell an official roll-up sides kit for the Caterpillar Tunnel Max at this time, but you're welcome to DIY it yourself if this is important to you. There are many resources online to help get you headed in the right direction.

How will this tunnel hold up to wind?

Thanks to the thicker diameter pipes, industry leading 14-gauge metal, and the Earth Lock anchor plates, the Caterpillar Tunnel Max has our strongest bow design yet, and the Earth Lock anchor plates at the corners keep it anchored better than any other method besides ground posts in concrete. Check out this article on Caterpillar Tunnels and wind over on our knowledge base for more general details.

How many 30” beds can I fit inside a Caterpillar Tunnel Max?

It depends on the width of your pathways. You can comfortably fit 6 beds with 12” pathways, and you could even manage to fit 7 beds with 8.5” pathways if you think the juice is worth the squeeze.

Does the Caterpillar Tunnel Max come with extra plastic to use for end walls?

No. But each Caterpillar Tunnel Max will include 10 extra feet of plastic (5-ft for each end) to give you enough extra wiggle room for easy installation. All of our end wall options will come with enough plastic to complete your door.

Tech Specs

Assembly & Instruction Manual

Classic Max Tunnel


2.51 MB pdf

Gothic Max Tunnel


2.55 MB pdf

Peak Height


12 feet, 11 inches


12 feet, 3 inches

Tunnel Width

21 Feet

Bow Diameter

1 5/8"

Bow Gauge

14-gauge gal­va­nized steel pipe

Plastic Width

42 feet

Plastic Rating

6-mil, 4 year

Purlin Type

1 ⅜” diam­e­ter 17-gauge gal­va­nized steel pipe

NRCS Specifications

Our tun­nels meet the basic 325R National NRCS spec­i­fi­ca­tions. Ultimately, you should con­tact your local NRCS rep and pro­vide our instal­la­tion man­u­al found at the top of this page and the spec sheet(s) attached to our knowl­edge base arti­cle, ​“Do your tun­nels meet NRCS spec­i­fi­ca­tions?” for their review. Also, check out the NRCS guide below for step by step instruc­tions on how to apply!

NRCS Documents and Guides

Product Reviews

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Recent reviews

This Max tunnel will be the best investment any grower can purchase!

5 out of 5 stars

Ray T.4 months agoVerified buyer

If you are looking to maximizing your growing space on your farm, then the Max Tunnel is your answer. Designed with efficiency and productivity in mind, this new offering from Farmer's Friend enables you to grow more produce on a small plot than any caterpillar tunnel on the market right now.

See all reviews