How to Build a Garden Low Tunnel (for Free)

low tunnel complete
Low tunnel ready to protect plants from endless winter.

Like many Minnesota gardeners, I’m getting itchy to put some plants in the soil. I have lettuces and greens under lights in the basement and some tomato seeds planted, but not yet germinated, in a warmer spot upstairs, but that’s not the same. It’s still pretty cold here and as I write this post on Friday afternoon it is snowing. Ugh.

Given the rather gloomy forecast, I decided to take things into my own hands and build a low tunnel where I could plant out greens and keep some of the seedlings as they get growing. I’ve been reading a lot about season extenders in the past year or so. We had a great article by Colleen Vanderlinden on them in the September/October issue of Northern Gardener and I recently read with enthusiasm Barbara Damrosch and Eliot Coleman’s new book The Four Season Garden Cookbook, which includes lots of practical tips on using cold frames, movable greenhouses and low and high tunnels to grow food in colder climates.

One of the designs involved using welded wire fencing and plastic. I had both on hand and knew I could fashion something serviceable pretty easily.

plastic ties
To make a longer tunnel frame, I joined two sections of fencing with plastic zip ties.

Here’s what I did: I took a length of 4-foot tall welded wire fencing and cut it in two equal pieces using a bolt cutter, making the cut in the middle of a square so that each end had a little tail on it. (Careful, these are sharp.) The raised bed I have the tunnel over is about 3 feet wide by 8 feet long, and the two welded wire pieces were about 4 1/2 feet across — just enough to create a bend for the greenhouse effect. I joined the two pieces to form one long one using plastic zip ties.

Next, I laid a painting drop cloth on the floor of the garage and put the wire tunnel on top of it. (If you have a heavier grade of plastic sheeting, use that.) I pulled the sides up and attached the cloth by poking the wire tails through the plastic. I left as much plastic as I could on each end of the tunnel and on the sides. I plopped it on the bed.

tunnel in plastic
Sheathed in plastic, the tunnel is ready to go to the garden.

Now came the tricky part. We live in an area that is really, really windy, and I knew I would have a flying low tunnel if it was not secured. I ended up doing two things. On each end of the tunnel I placed a piece of 2-by-10 lumber about 3 feet long. (I happened to have these on hand from another project.) Then, I took some rope and lashed the plastic down in three places, tying the ends of the rope to some winter-sowing jugs. Any fairly heavy plastic jug with a handle to tie the rope to would work. Voila!

The tunnel stood up to a fairly stiff breeze last night with no problems. I’ll start planting seeds and putting out seedlings on Sunday, when the weather is predicted to be a bit warmer.

It’s rare that I have all the equipment on hand for a project like this but this time I did.  There are many videos on youtube about hoophouses and tunnels. While the production quality isn’t great, this one has good step-by-step information on how to put together a low tunnel using PVC pipe and plastic.


Deck Garden, Year 2

Deck garden today (that’s my brother’s foot in the corner.)

Last summer, I wrote two posts (here and here) on how to build a garden box for a deck, based on the one created by my sister and her husband. They hosted a barbecue on the 4th of July this year, and I got a chance to see how the deck garden is doing in its second year.

The answer: great! They planted different tomatoes this year, opting for slicers rather than cherries, and have plenty of green ones on the two plants growing in the box. They also have several beautiful looking basil plants, as well as oregano, parsley, rosemary, and chives. All of this is just outside the door to the kitchen, making it convenient to snip a few herbs for cooking projects. The deck box, which is made of cedar, remains attractive, despite heavy rains this year and its sunny location.

Bee Condo Update: Solitary Insects Move In

As I noted a while back, critters have taken up residence in my bee condo. But they do not seem to be orchard mason bees. When an orchard mason bee moves into a condo like this, the signs are a rough mud plug in one of the holes. The bees use the holes to protect their offspring and fill the holes with baby bee food before plugging it up for safe keeping.

I have mud plugs, finally, but they are not rough. They are smooth, which I originally thought was a wasp, but the holes also include lots of cut up grass, which is not the usual m.o. for orchard mason bees. I did manage to catch a photo of one of the occupants leaving the condo the other day. He is longer than a bumble bee, also thinner, with a pronounced waist. Unlike the orchard mason bees, which are usually bluish, this bee was black and yellow.

Having long ago reached the limits of my knowledge of insects, I sent the photos above to David Zlesak, an extension educator at the University of Minnesota, editor of the U’s Yard and Garden News, and an occasional contributor to Northern Gardener. David is not a bee guy, but he knows an insect guy–Jeff Hahn–who checked out my photos and determined that it’s probably a leaf-cutting bee living in the bee condo. Leaf-cutters are solitary insects and effective pollinators. Their only negative is the leaf-cutting. I do have quite a few plants showing holes, especially one rose, further confirming the leaf-cutter theory. As Hahn noted, “They probably like your house just fine.”