Use Low Tunnels to Grow Veggies in Winter; Gardening Guidebook

8/9/2019 Use Low Tunnels to Grow Veggies in Winter; Gardening Guidebook

1/5MEN - Use Low Tunnel s to Gr ow Veggi es i n Wi nter - Qui ck Hoops. doc 1/ 22/ 2010 3: 53 PM Page 1 of 5

http://www.motherearthnews.com/Organic-Gardening/Low-Tunnels-Quick-Hoops.aspx 1/22/2010

Use Low Tunnels to Grow Veggies in Winter: Quick HoopsBy Eliot Coleman

As a farmer, Im always looking for new ideas and simple, low-cost solutions to improve production and efficiency. I havenever found any activity that cannot be improved (and then improved again) by a diligent process of critical evaluation.Long before my wife, Barbara Damrosch, and I came up with the design for our low tunnels (miniature greenhousetunnels), we had already improved our greenhouses by making them moveable, first on skids and later on wheels. Butinnovation is anever-endingprocess. Theideal solution isalways lessexpensive,simpler to buildand lesscomplicated tomanage. Weconsider itpleasant mentalexercise torefine allaspects of ouragriculturalproduction tothe essentials.

Using these inexpensive low tunnels, you can protect plants throughout winter for a fraction of the cost of building agreenhouse.

For a harvest of mature onions in early summer to sell at our farm stand,we were interested in growing the fall-planted onion varieties listed in seedcatalogs. Olympic, an overwintering onion from Johnnys Selected Seedshas become our favorite variety. It only keeps in storage for a few months,but thats no problem because they all sell by the time later onions areharvestable. Because the low temperatures here in Maine are too harsh foroverwintered onions to survive, we needed to grow them with protectionfrom the weather. We decided to grow them in one of our unheatedmoveable greenhouse rotations.

Eliot Coleman uses low tunnels to grow carrots, salad greens and othercrops in winter in Maine!

We drilled the seed in late August, left the onions uncovered until we had

harvested the last of a late sowing of greenhouse-protected lettuces justbefore Thanksgiving, and then moved the greenhouse to cover the onionsfor winter. To be sure there would be sufficient winter protection, we put aninner layer of floating row cover supported by wire wickets inside thegreenhouse. In late March when we moved the greenhouse, the worst ofthe winter cold was over. The onions looked green and beautiful, and theymatured in June to give us the early harvest we had hoped for.

But we knew we could do better. Although we had onions to sell in June,we hadnt sold anything from that greenhouse all winter. In another mobilegreenhouse rotation, we had harvested mid-September-planted spinachfrom mid-November right through the winter. And in April we followed thatspinach crop with transplants of Tuscan kale, which we were also selling inJune. The demand for winter spinach was insatiable, and we would gladly
http://www.motherearthnews.com/Organic-Gardening/Low-Tunnels-Quick-Hoops.aspxhttp://www.johnnyseeds.com/http://www.johnnyseeds.com/http://www.motherearthnews.com/http://www.johnnyseeds.com/http://www.motherearthnews.com/Organic-Gardening/Low-Tunnels-Quick-Hoops.aspx



have had that onion greenhouse filled with spinach. But the onions were a great crop. We started thinking about simpler,less-expensive protection than a greenhouse.

Low-tunn el Greenhouses

Because the spinach was harvested all winter, it needed to be in a greenhouse in which we could walk and workcomfortably. But the onions were just hibernating for the winter, so to speak, so we didnt need to walk in and visit them.We decided they should be able to survive under lower, less expensive winter protection.

We knew the wire wickets that supported our floating row covers wouldnt hold up under winter snow, but we thought that

sturdier low tunnels might work. When we looked for materials to construct the low tunnels, we realized that 10-footlengths of half-inch electrical conduit would be ideal. A 10-foot length of conduit bent into a half-circle with the endsinserted in the soil covers two of our 30-inch-wide growing beds with a 1-foot path in between. What we came to callquick hoops were born.

To make the low tunnels, we started with half-inch metal electrical conduit and made three 60-degree bends with aconduit bender to create a house shape straight side walls (6 feet apart) and roof sections slanting equally to bothsides. We assumed we would have enough support if we used one hoop every 5 feet. We then covered this prototypewith a 10-foot-wide floating row cover held down along the edges with sandbags. We found that holding the edges of thefabric with sandbags is much less work, much faster and almost as secure as burying the edges. We fill each bag with 12to 15 pounds of soil, sand or gravel.

These low tunnelsare covered with

floating rowcovers. Beforewinter, a layer of

plastic will beadded.

A few windy daysshowed us aweakness in thisdesign. The rowcover fabric wasstressed where itwas pulled tightlyagainst the threebends of thehouse-shapedhoops and wastorn in a fewplaces. Werealized that asmooth, roundshape for thehoops would bepreferable.

Our next step was to make the hoops out of half-inch hard-plastic conduit. By making 10-inch-deep holes with an iron barevery 5 feet along the outside edges of the two beds, we could insert an end of the plastic conduit into one hole and

carefully bend the conduit into a half circle, inserting the other end into the corresponding hole.The first time we put up the plastic hoops, two people working together made the process easier: one holding the first endvertical while the other bent the conduit and inserted the second end as vertically as possible. After being used for awhile, the conduit acquired a reasonably curved shape that made erecting the hoops an easier job for one person.

We put hoops over the onion beds in mid-October. Realizing the tunnels would have to survive the weight of winter snowand that we were now using plastic instead of metal conduit, we doubled the number of hoops by placing one every 2 1/2feet along the row. We covered the hoops with row covers after we put them up, and the onions continued growing. Butfor the serious winter weather that would be starting by late November, we knew we needed a stronger material than thefloating row cover fabric.

We had just re-covered a greenhouse, and the old plastic still had a little life in it, so we cut it into 10-foot wide strips andset them aside to use when the weather got colder. We planned to place the plastic over the fabric in order to give the lowtunnels a smooth, strong surface for the snow to slide off.



The final step, completed around Thanksgiving, was to add the plastic and stiffen the structures against the weight ofwinter snow to come. We drove a 2-by-4 stake into the ground 3 feet from the end of each row and tied a rope tightlyaround the bunched end of the plastic covers (see illustration in the Image Gallery ). We then pulled the ropes as tightly as

we could from both ends to make thecover taut and tied the ropes to thestakes. We replaced the sandbags tohold down both the plastic and the fabric.

Both that first winter and again this past

winter, the snow here on the Maine coastdid not disappoint us, and the quickhoops got a real test. With the exceptionof one end of a row where the snowdrifted excessively and pressed a few ofthe plastic hoops down to the ground, the30-inch high tunnels survived a numberof 18-inch snowfalls with aplomb.

Broccoli, cabbage and many other cropswork well under quick hoops.

Even Better Designs

Are we satisfied? Of course not. We recently perfected a tubing bender to create the ideal curved shape from half-inchmetal conduit. With the proper curve, metal conduit hoops with almost straight sides extending 6 inches or so above thesoil come closer to the ideal shape. We need only half as many hoops (back to the 5-foot spacing) to hold up under thesnow.

Pre-bent metal hoops help in another way. The plastic conduit tends to lean in toward the beds where its inserted into thesoil, because of the forces against it. The leaning reduces space along the edges of the beds when we use the hoops forprotecting other crops that need more headroom, such as early brassicas, beets, carrots, lettuce, melons and zucchini in both spring and fall.

We always strive to achieve our goals in the least expensive way. Quick hoops do well in that respect. Using the quickhoop system, we can give winter protection to 1,000 square feet (the size of a 20-by-50-foot greenhouse) of overwinteredcrops for about $100 only 5 percent of the cost of protecting that area with a greenhouse. (The cost for our low tunnelsis about 10 cents per square foot.)

Which crops work well under quick hoops? Spinach would be an obvious candidate. New England growers havetraditionally sown outdoor spinach in the fall, giving it a little protection with evergreen boughs, in order to get an extra-early harvest in spring. Many other hardy greens, such as lettuce, could also be planted in the fall for early spring harvest.We have often seen our latest-planted baby leaf salads for fall harvest successfully winter under a layer of snow andcome up again in the spring much sooner and more vigorously than a spring-planted crop could ever do. Because onecant count on snow cover, quick hoops are an excellent substitute. And what about a late-fall sowing of early-spring cropssuch as peas, carrots or beets? Hopefully, they would survive to germinate and start growing a month or two ahead ofschedule in the protected shelter of the low tunnel. A new idea always leads us to more new ideas.

One more important thing: Think about venting the hoop tunnels so they dont overheat when the sun returns in latewinter. We simply remove some sandbags in a couple of places and use stakes with a V-notch in the top to hold theplastic and fabric a foot above the ground. By the end of March, we remove the plastic layer on each hoop tunnel andstore it for future use. At that point, we have a fabric-covered low tunnel that we leave in place until it is no longer

necessary or we need to move the hoops to another crop. It couldnt be easier.Good Crops for Low Tunnels

Beets Broccoli

Cabbage Carrots

Lettuce Onions

Peas Spinach

Make a Tubing Roller

If youd like to bend metal conduit (electrical metallic tubing) into arcs (instead of forming a corner with a common tubebender), Eliot Coleman has designed a tubing bender that will be available from Johnnys Selected Seeds next spring. Ifyoud like to make your own tubing roller, read Mothers Homemade Tubing Roller . (See photo in the Image Gallery ).
http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807http://www.johnnyseeds.com/http://www.johnnyseeds.com/http://www.johnnyseeds.com/http://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspxhttp://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspxhttp://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspxhttp://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807&seq=3http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807&seq=3http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807&seq=3http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807&seq=3http://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspxhttp://www.johnnyseeds.com/http://www.motherearthnews.com/multimedia/image-gallery.aspx?id=2147484807



http://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspx

Mother's Homemade Tubing RollerBuilding a metal tube roller to bend tube for greenhouses and other buildings to save money. September/October 1980By the Mother Earth News editors

Beat the cost of custom conduit shaping by building . . .

If you've already read the backyard greenhouse article on page80 of this issue, you know that one of the tools required to buildthe little "sun shed" is a tubing roller. Now such a deviceifpurchasedcould cost you several hundreds of dollars,because it's normally a motor-driven "professionals only"machine.

A roller is used to shape lengths of standard conduit orelectrical metallic tubing (EMT) into arcs (rather than merely toform a corner, as is the case with the far more common tubebender) for use in framing, toolmaking, and other kinds offabrication. On several occasions MOTHER's shop crew hasfelt a sore need for one of the handy implements . . . so finallythey just up and built their own "North Carolina copy", which

fills the bill perfectly!HERE'S HOW IT WORKS

Most store-bought tube-shapers run on electricity. Our version,though, uses a handcrank that not only feeds the conduitthrough swiftly and easily, but costs nothing to operate. Thetool works like this: The bender itself is simply a pair ofcrosseseach made of two 18-inch long 2 X 4'sthat"sandwich" a set of three grooved pulleys and a pair of support blocks. Two of the wheels (those that are in line along thesame crosspiece) serve as idlers ... and the third pulley (positioned at one end of the other crosspiece) is the driver.

When the straight conduit is placed between the driver and the left idler, and the crank is turned, the tubing moves alonguntil it contacts the right idler, which forces the pipe to bend slightly (see the photo below) and to continue to bend till theentire section is arced. (This happens, of course, because the driver is positioned close enough to the idlers to force theconduit to bow.)

AND IT'S EASY TO BUILD!

The only tools you'll need in order to make this inexpensive device are a drill with an assortment of bits, a couple ofwrenches, and a table saw with adjustable fence and blade height. Start by locating a good piece of 3/4" seasoned oak that's at least 5" wide and 30" in length. (While you're at it, findor plan to cut from the first board, if it's large enough another section measuring 3/4-inch X 1 1/2-inch X 12 inches . . . which will become the arm of the turning handle.)

Next, cut theplank in halfand glue thetwo sectionstogether sothatwhen itdriesyou'llhave asingle pieceof woodabout 1 1/2inches thick... fromwhich you'llcut three 5"X 5" pulleyblanks. Todo so, setyour saw
http://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspxhttp://www.motherearthnews.com/Do-It-Yourself/1980-09-01/Homemade-Tubing-Roller.aspx



fence 5 inches from the blade andbeginning with a shallow cut and working progressively deeperpass each blankthrough the saw, rotating the wood slightly at every pass, until the disks are perfectly round.

You can use the same method to form the grooves in the pulleys. Tilt the saw blade at a 45 angle, then set your fence 11/2 inches from its near side. Raise the blade 1 inch from the table (measured along the toothed disk's side), and pass theedge of the wheels through it. When the incision is complete around the entire circumference, turn the wooden circle overand cut the opposite side of the groove. (WARNING: During all of the foregoing sawing procedures, be extremely careful... remember, your fingers will be very close to the area being cut!)

Trim the rest of the wooden components from a 76" length of 2 X 4, round the ends of the oak handle arm, and cut half-lap joints in the center of your crosses . . . then refer to the illustration provided for aid in assembling the roller. (NOTE:The critical measurements are [1] the 8-inch center-to-center distance between the two idler pulleys, and [2] the 4 1/2-inchspan from the axis of the drive wheel to the midpoint of that 8-inch centerline.)

BUT THAT'S NOT ALL. . .

This little gadget can't be beat for bending the support ribs on our "shoestring" greenhouse. What's more, if you take a tipfrom MOTHER's Emerson Smyers, you can use the tool to perform any number of other tube-shaping chores: "Lengthenthe channels in the lower section of each cross," Emerson says, "and slot the 1/4" mounting holes so the drive pulley canbe moved closer to or farther from the others but can still be locked in place where desired. You can then produce justabout any kind of arc . . . even those required for large parabolic mirror frames!"

Documents

Use Low Tunnels to Grow Veggies in Winter; Gardening Guidebook