Caterpillar Tunnel Workshop, class of ‘14

Pre-workshop site

Last Sunday, we hosted a hands-on workshop called Extending Your Season with Caterpillar Tunnels, presented by ACORN’s Grow a Farmer program as part of their Learning Series. The timing was great as we’re in the midst of putting up 5 caterpillar tunnels (3 for vegetable crops, 1 for cut flowers, and 1 for vegetable seed crops).

If you look back on this blog (here), you will see that we wrote about putting up the caterpillar tunnels a few years ago. There have been a few changes since then that we will highlight in this blog post.

I really want to thank the participants of this workshop for coming up and being interested in this subject and working their butts off to help us put up these tunnels. I like to think of our farm as a quilt and all the participants definintely created their own patch that will live on and be rememebered with gratitude.  We were also fueled with some very generous (and delicious) food donations from the wonderful Sequoia Natural Foods in Moncton (who we supply produce to during the growing season) and Just Us Coffee in Wolfville.

The picture above is basically what the area looked like when participants arrived.

The pictures below show one change we’ve made, and that is to use landscape fabric for the tunnels that will be in the same spot for the whole season or longer. This is due to the fact that it is very challenging to try to weed and/or mow the spaces in between the bows. With 2 of the tunnels, we laid landscape fabric over almost the whole thing leaving just strips where we’ll be planting tomatoes. You can see the fabric staples being put down along the edges to keep them in place.

Bryan stapling geotextileShaani stapling geotextile

Previously, we used wooden stakes under each bow which were much cheaper (they were free) than the rebar we’re now using. This is a result of the change we’ve made in gound anchors. Hopefully, overall it will make things easier but there definitely was a lot more stake pounding initially. You can see in the first picture we were making small cuts in the fabric to put the rebar through.

Putting in the rebar stakesPounding the stakes in

We’ve been using PVC pipes as the arches which we’re still happy with overall. They are extremely easy to bend (we just bend them right over the stakes) and they have a bit more flexibility (than metal hoops) with snow loads in the winter.

Straight PVC pipesBending PVC pipes

So, here you can see the new anchors we’re using. Our previous ground anchors were Duckbill anchors which snapped too often for our liking. Even though they’re strong enough, I don’t think they are good for the amount of water that can come off a tunnel and the galvanized steel would rust and break. So, now we’re using galvanized steel plates (2”x 4” with two holes drilled in them at each end) that slide over the rebar, and have a stainless steel snap clip to attach the rope to.

Anchoring systemSnap clips attached to plates

Anchor plates and ropeRopes attached to snap clips

We use t-posts at each end of the tunnels to hold the “ponytail” of plastic covering at both ends. I like the 2 beards in the lower picture.

T-posts on endsPounding in t-posts

 

Tunnel ponytail

We had a great 7 year old helper named Marina who did an amazing job at running the rope around the whole tunnel.

IMG_0606

And she was a real quick learner when Bryan showed her how to make the knots.

KnotMaking a loop and tying it

Another difference this year is that our tunnels will be moved and/or adjusted for the winter. We like to keep them up over winter but the arches need to be spaced closer. In the past, we’ve just kept them at 4’ spacing all year and over winter. Now, we’ve got them at 6’ spacing over summer (when we don’t need the extra reinforcement) so we can have more tunnels up over summer with the same materials.

TunnelInside tunnel

Below is the updated list of where we sourced the materials for the tunnels and their cost. The last 2 columns show the difference in cost per tunnel if the tunnel has arches with 6’ spacing or 4’ spacing.

Tunnel "recipe"

Here is a link to download the .pdf of our material and suppliers list: Caterpillar Tunnels at Broadfork Farm handout

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10 Responses to Caterpillar Tunnel Workshop, class of ‘14

  1. Greg Daggett says:

    We had our plates made at a local machine shop for around $1/each. Take the design, have them copy it, save a few bucks and support a local business. Win win!

  2. leonard Vassallo says:

    The caterpillar tunnels handout pdf did not load up?

  3. eric stoffer says:

    Thanks so much for posting this information. If I was closer to you I would have helped out for sure. Out plan is to install some caterpillar tunnels this fall so we are ready for spring 2015.

    There seems to be a problem with the links on with this post as they redirect back to the blog post itselft.

    Thanks

    Eric

    • broadforkfarm says:

      Great to hear from you Eric! I checked out your website and really enjoyed it! Ok, so I just fixed the pdf link. It should work now but let me know if it doesn’t.

  4. Jennifer says:

    Hi, I keep referring to this post, great stuff! We’re down by Yarmouth. Where did you get your landscaping fabric and what was the cost? I don’t see it in your price breakdown. Thanks!

  5. Jennifer says:

    Excellent! Got ours from DuBois a couple of weeks ago! We’d love to drop by sometime, this is our first year (late start) doing a market trial on a very small scale. :)

  6. Matt Coffay says:

    Hey,

    We’re thinking of using these for winter production this year. We’ve used them during the summer with no issues (they’re great), but I’m a little concerned about wind and ventilation during the winter. We do a second layer of protection over our winter crops (19 gram Agribon fabric), but normally we’d be venting a winter greenhouse with roll-up sides that open midway up the sides of the greenhouse, leaving the bottom few feet of the sidewalls intact to protect the plants from harsh winter wind at ground level. Have you had any problems with rolling up the sides of the caterpillar houses and the desiccating effects of winter wind? We’re not in a super harsh winter climate (Asheville, NC), but we do get some snow and a good number of days with temperatures in the teens at night. Thanks!

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