want help to built Low Tunnel

[shardul]

Hi can any one please give me detailed structural information on building Low Tunnels?

Thanks & Regards
Shardul....

[johno]

You need two things - arcs and plastic. Plastic is easy to come by. The arcs you'll most likely have to make yourself.

How I made mine... I bought 3/8" diameter rebar from the concrete company, cut the 20' lengths into 1/3rds with (big) bolt cutters (but you can use a hacksaw or grinder or carborundum blade,) and bent them into arcs using a form I made. The form was a sheet of plywood with the arc drawn on it (considering the width of my growing beds) and 2x2 blocks screwed to the form at intervals of about a foot, starting at the apex. I put the center of a length of rebar onto the top point block, lifted the ends in each hand just high enough to clear the other blocks, and pulled the initial bend into it. Then lowered the rebar enough to just catch the next two blocks and pulled some more bend, and so on. This is much more difficult than it sounds.

I would definitely use 1/4" steel rod (found at the concrete block plant) next time! I suppose there are some brighter ideas on how to make the bends, too, but that's what I came up with...

Another thing I would do differently is to cut the 20' lengths in half, not thirds, because the plastic I get is ten feet wide. By the time you push the arcs into the soil, there would be just the right amount of plastic on the ground on either side instead of way too much... Also these would make higher low tunnels which would concievably be useful to extend the season (with taller plants) rather than just get a jump on it.

Anyway, I also spray painted the arcs, extra coats at the ends, to make them last longer.

I push the arcs into the ground along the outside edges of the beds at approximately 4' intervals. You can use boards or something longish and somewhat weighty along the long sides to hold the plastic down, and at the ends you want to use big rocks or concrete blocks to hold down the folded-over excess. On warm days I leave the ends open or it gets too hot.