Winter Caterpillar Tunnel Structural Trial (2011)

In March 2011, we tested our caterpillar tunnel under heavy snow load to see how the structure would respond. Now that winter is upon us, we're re-posting our results from the trial. Let us know your thoughts on our findings by leaving a comment under this post!

Goal: To see if either caterpillar tunnel version (with, or without purlins) could withstand winter snow load.

Results: Very interesting. We picked two of the four tunnels that were built in May, 2010, planted onions in them, and buttoned them up for the winter. Both tunnels were structurally the same, with a center ridgepole made of chain link fence top-rail, but one of them also had purlins about three feet from either side of the ridge. These purlins, were used in the summer to trellis vine crops, and carried that load quite well. They really stiffened up the whole structure. However, in summer, they tended to cause the plastic to collect rainwater. This made me think that the purlins would either make it so strong that it would better carry the snow load or they would catch more snow than the tunnel without purlins and cause a collapse. It looks like the latter is the case.

Summary and recommendations: It is important to note that we intentionally did not remove snow in this trial, as we were looking for structural failure in worst case conditions. Removal of snow, even just next to the tunnel that failed, probably would have prevented its failure. Doing so would have greatly reduced the pressure bearing in on the sides (and therefore the plastic's weight felt on the top). If you intend to use a structure like this to overwinter crops in northern climates where snowfall is a concern, I would recommend a maximum of four foot bow spacing during construction, not using side purlins in winter tunnels because they catch snow, and, of course, the removal of snow whenever possible from the sides and top of the tunnel. It would also be prudent to shore up the bows internally with notched two-by-fours placed vertically under every other bow as a means of additional snow load insurance and peace of mind.

You can view the complete gallery of this trial below:

The 26-page illustrated manual for the bender used to make these tunnels may be downloaded on the Quick Hoops™ High Tunnel Bender's product page.


Adam Lemieux
Johnny's Tools & Supplies Manager

Johnny's in the news: Recent articles, cabbage

It's that time of year when the gardening press, with seed catalogs in hand, gets excited about the upcoming growing season. We're always thrilled and very grateful to be mentioned in newspapers, magazines, blogs, new media, etc.

Here are a few recently published articles about our 2011 catalog and products.

"It’s not too early to think about fat, juicy tomatoes". This Providence Journal article, by gardening columnist Henry Homeyer, focuses on our new Defiant PhR tomato and our tomato breeding program. Henry interviews Rob Johnston Jr., Johnny's Chairman and Founder, and Andrew Mefferd, our tomato Product Technician.

"Vision of what might be" This is a Worcester (Mass.) Telegram story by Paul Rogers about Johnny's 2011 catalog.

A review of Johnny's 2011 catalog from the "His and Hers Homesteading" blog. Very complimentary. We're tickled pink. Thank you very much indeed, Courtney and Robert!

And here's a bonus story that doesn't mention Johnny's. It's a New York Times piece about cabbage: "Cabbage's Sweet Side". It's a very good read.

Johnny's new and improved virtual catalog online now

If you haven't received your 2011 Johnny's Catalog yet, you can take an online sneak peek at it now.

We've recently published Johnny's electronic catalog on the website. Check it out here.

It has the same look and feel as our printed catalog and also has some great interactive web features.

Coming soon: Johnny's 2011 catalog with 200 new products!

This is one of the most exciting times of the year here at Johnny's.

The big news? We've just printed the 2011 catalog. You should be receiving your catalog within the next 6 weeks, or so. This year's edition contains more than 200 new products, including 75 new organic seed varieties and 6 new Johnny's-bred varieties.

A few highlights:

Defiant PhR tomato: from the Johnny's breeding program; a mid-sized slicer with full resistance to late blight and intermediate resistance to early blight.

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