I don't think we've had the occasion to properly introduce our tunnel yet, even though we've had it and used it (quite unproductively) for quite a few years now. So let's take the opportunity of a brand new plastic covering to present it to you (before it becomes dirty and starts to degrade).
We're used to calling this structure a hoophouse, although its size (about a meter tall at its highest) doesn't make it a proper "house", but rather a tunnel (or "chenille" AKA caterpillar, as the French would put it). Tunnels are widely used in field horticulture for various purposes, but nothing says we folks can't make our own and use it at home.
What's it good for, though?Many things, actually.
1) You can use it to cover seedlings before they're ready for transplanting. If you are growing your seedlings at home, there might come a point where you will be able to move them to the tunnel to finish their growth before transplant. The tunnel may offer some protection to the cold night temperatures depending on its location.
2) You can also move it over a garden bed, instead of using it on an hard surface as we do (although setting hoops directly into the ground - about 2 feet deep - might be the best option here). Take note that pests already established in the garden will thrive under a tunnel, so be careful. The tunnel warms the soil and may be used to:
- thaw a garden bed faster in the spring
- start an extra early-season crop (that can be uncovered later in the spring as the soil and air warm): lettuce, spinach, mâche, radish, kale, peas, asian greens, leek, etc.
- delay a late-season crop (that was started uncovered earlier in the summer or fall): carrots, beets, lettuce, spinach, asian greens, radish, tomatoes, squash, etc.
- start a summer crop earlier: tomatoes, cucumbers, squash, etc. can be planted as seedlings a few weeks earlier if they are protected by a tunnel.
Basically the tunnel can be used to extend the growing season. The best season is the longest season (like winter, right?).
3) Preserve a winter harvest: Some late fall crops can tolerate below-freezing but near-zero temperature without damage if they are allowed to heat up during the day. Some crops, like baby carrots (i.e. premature carrots), can also be conserved until November if covered with a thick mulch of straw; the cold breaks up the starch in the roots into sugars, resulting in the sweetest "candy" carrots.
4) You can lay in the tunnel in mid-April and pretend summer has already arrived.
How it's madeIt's pretty simple and straightforward, and is open to lots of improvements and tinkering to better suit your needs.
-wood planks, we used 2x4 to make a structure of dimensions 8x3 feet
-power drill and a 1½-inch wood spade bit
-1-inch PVC pipes (the flexible, grey types)
-plastic sheet big enough to cover the hoops with a few extra feet on all four sides
1) Put together a wooden frame of the desired size. If you want to use the tunnel in the warmer months and be able to ventilate it properly to avoid killing your plants, the tunnel can be ventilated properly by uncovering only the end walls if its length is no more than three times its width (or so says Eliot Coleman). If it's longer than that, you will need to remove more than just the end walls to allow proper ventilation.
When making the frame, make sure that the planks are laid flat (the wider side facing up). You can join them by putting wooden blocks as props at each corner, in which you can screw the planks.
2) Make 1½ inch holes every 2-3 feet along the length of the frame. Make sure the holes on one side of the frame are well aligned with the holes on the other side, as these will be used to insert the hoops. Make sure too that you have holes to insert hoops at each end of the frame.
3) Cut 1-inch PVC pipes in equal lengths. The length of the pipes will determine the height of the tunnel. You can test them by inserting one end in a hole in the frame and bending the pipe over to the hole on the other side to see how long the hoops should be. Usually a tunnel is 60cm (2 feet) high.
4) Install the hoops and cover the tunnel with a large sheet of plastic, preferably UV-resistant. You can attach the plastic sheet to one half of the hoops with zip ties if you want (as long as you're still able to lift one side of the plastic sheet to have access to what is in the tunnel). You can pass the zip ties through washers on both sides of the plastic sheet to minimize damage (the tension in the plastic can cause the holes to enlarge through time).
It is also possible to wrap and fasten the extra length of plastic on each long side of the tunnel to pieces of wood (see our tunnel). This helps weighing down the plastic during windy days.
So that's it, we hope you enjoy your tunnel! Other small-sized garden protections include the covered A-frame (which is really just an A-frame covered with a plastic sheet to extend the tomato season), and the age-old cold frame.
BONUS: Pictures of the garden set up
|Tulips, they never die.|
|Some spinach seeds left from last year decided they would sprout.|
|The rhubarb looks very healthy so far!|
|The motherwort is getting bigger, too.|
|Looks like we'll have plenty of strawberry blite seedlings to cover this bed!|
|A strawberry blite seedling.|
|While digging up the garlic to put all the bulbs on the same bed, we found some small parsnips from last year. We'll see if they can grow properly this year and maybe set seeds.|
|One of our kale plants bolted early last year and dropped its seeds on the bed. This year, tiny kale seedlings are popping out of the ground!|
|The garlic bed. We'll add some leeks and onions (mostly onions) to keep it company in about a week.|
|It took me a while to find it, but we transplanted this blackberry seedling last year in the hope that it would finally establish somewhere for good. We're not sure if it's still alive...|