The Walden Effect: Farming, simple living, permaculture, and invention.

Caterpillar tunnels: Hinged quick hoops for pest control

Caterpillar tunnel

Mark's taken advantage of the lockdown to perfect a prototype for what we're calling caterpillar tunnels. The idea is to block cabbage white moths from laying their eggs on crucifers. I've used row-cover fabric for this purpose in the past, but the thicker cloth overheats cool-weather crops. Plus, Mark wanted to improve upon my quick hoops, which are a bit of a pain for frequent ingress.

To cut a long story short, he tweaked and came up with a no-work organic solution for controlling of one of my least favorite pests --- cabbageworms. Of course, I mean no work for me once the caterpillar tunnels are installed. Building them was work for Mark!

Framing garden protection

He started with 2X3s, a compromise between what he wanted (2X6s for longevity, but which I argued would shade plants too much and be too heavy) and what I wanted (2X2s, which he considered too flimsy). It still counts as meeting in the middle if he comes almost all the way over to my side of the fence, right?

Adding hoops to a garden bed

After building two frames out of 2X3s and hinging them together along one long side, Mark used a 3/4-inch hole saw to install our usual quick hoop pipes (1/2-inch PVC). Your measurements can match your garden, but ours were:

  • Frame --- 8 feet by 4 feet for maximum use of lumber
  • Pipes --- 6 feet long

Painting a caterpillar tunnel

A furring strip along the top gave the hoops a bit more rigidity while also providing something for the eventual covering to bite into. Since we didn't have treated lumber on hand, Mark gave it all a good coat of barn paint.

Building handles out of lumber

Oh, and did I mention handles? For the first prototype, Mark had some really awesome storebought handles to use. But for the later ones, he's building our own out of wood.

Wedding tulle as caterpillar netting

Anyway, back to the prototype. We covered it with wedding tulle, which  will let air and light through (meaning it's summer-garden friendly) without allowing in bugs. Various forums suggest this stuff lasts almost as long as the much-more-expensive garden netting you can buy from farm-supply sites.

Plumbing strap to attach tulle

How did we attach the tulle? Mark used plastic plumbers' strapping plus screws --- fast and easy as long as he borrowed another set of hands (mine) to hold the tulle in place.

Did you notice the small rip? Be careful! Splinters can damage your covering as you pull the fabric tight.

Opening stop

Mark also used the plumber's strapping to prevent the top from hinging all the way open. This way, it won't fall on the bed behind it and is easy to grab and pull back closed.

Caterpillar tunnel in the garden

Here's the finished product, taking over for my quick-and-dirty tulle-only covering. The broccoli are enjoying having room to stretch out.

Oh, but, honey, I need three more....

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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.

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What a great design! I'm growing brassicas for the first time and I've been warned to protect against cabbage worm. Some people here (Berea,KY) don't even bother growing them until the fall for that reason. I currently have a heavy white row cover over them and need to find an alternative - this could be it!
Comment by Rhonda from Baddeck Fri Apr 24 12:56:49 2020
Super cool! Are the pipes just held in with a screw, or are there holes drilled for them to nest in? I'm absolutely going to dig out some scrap this week and try something like this with greenhouse plastic.
Comment by Trav Williams Mon Apr 27 00:05:48 2020

Hello out there! Great tip on the tulle. I just watched a little cabbage white float around and drop some eggs on our kale. Do you think black tulle might work as an alternative to shade cloth? Or perhaps just the white in a few layers could work..? Really enjoying the tips on here as an Ohio gardener.


Comment by Sarah Fri Jun 5 15:10:07 2020
Comment by Howard Fri Aug 14 21:02:41 2020

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