Discussion forum for the various methods and structures used for getting an early start on your growing season, extending it for several weeks or even year 'round.
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February 27, 2012 | #1 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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vinyl vs plastic for low tunnel
I picked up some vinyl at the dollar store this winter, to try out window coverings that let light in while reducing the cold breeze on my plants (and me!). These are heavy, supple pieces of vinyl 52" X 90" selling for $2 as a "Tablecloth protector". They are not as translucent as I would like - you can't see clearly through them - but they do admit a decent amount of light and block the cold really well for a single sheet.
I am thinking of using these to make some low tunnels for summer squash and bush beans. The advantage of vinyl over plastic is that it's stronger and machine sewable - so I can sew on the channel for a wire hoop to be attached, etcetera. Plastic doesn't work well for greenhousing in our climate: you have to staple it on, it's too mucky and stiff to fold up neatly and bring in for the winter, and it freezes and shatters if you leave it out. Does anyone have experience using vinyl in the field? And how does it compare with plastic. I did a mock up hoop with some heavy wire I have on hand, and I reckon I can build 5 foot long tunnels, 18" high and 30" wide, for less than $5 apiece. I am going to try this anyway, but experienced advice would be appreciated to keep me from making a beginner's mistakes! We had really high UV last summer: 8 or 9 every day the sun shone. I know that has an effect on any kind of plastic but I have very little experience with vinyl..... Do you think it will be toast by the end of the summer? I don't even know if slugs and snails are attracted to it! |
February 27, 2012 | #2 |
Tomatovillian™
Join Date: Feb 2012
Location: Maryland's Eastern Shore
Posts: 993
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If the material is not UV stabilized it will yellow and get brittle in fairly short order. The commercial grade plastic for hoop houses may be a better choice. We have had a mild winter to be sure but the material we used is holding up well. Below is a picture of our tunnel. It is a row cover we started out with and then clear plastic from Johnny's Seeds over the top. It has been out about 3 months now.
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George _____________________________ "The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants. It is it’s natural manure." Thomas Jefferson, 1787 |
February 27, 2012 | #3 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Thanks, George. Your advice is much appreciated. I won't invest too much time in construction details then, since there's a good chance it will break when I try to fold it.
I might try using it early in the season and then taking it away completely when the hot weather comes, try to get a longer cycle out of it that way. I do have some row cover I could use over it if we get a bout of high UV weather - that would probably be best for the plants as well. I can't afford any specialty materials at this time, so I will test this stuff and see what happens. |
February 27, 2012 | #4 |
Tomatovillian™
Join Date: Feb 2012
Location: Maryland's Eastern Shore
Posts: 993
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I hear wht you are saying about the specialty plastic. I need to get at least a couple seasons from mine to keep me from feeling pound foolish for buying it.
I'm not sure how much temperature gain you are going for but I noted this past fall that just the row cover can do more than one might expect. On days of 60 degree F highs I saw afternoon temps under the cover over 80 F. I'll be interested to see how you make out. Usually for my bush beans and squash I am trying to figure out how to keep them a little cooler and still keep their foliage drier...
__________________
George _____________________________ "The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants. It is it’s natural manure." Thomas Jefferson, 1787 |
February 27, 2012 | #5 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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The problem here is, we have very cool summers. And windy. And sometimes (okay fairly regularly) overcast, rain, fog, and low light. Then the sun shines and we have scorching UV (at least the last couple decades and getting worse). It's difficult to establish squash and beans, because they don't like those conditions, especially the squash seedlings simply perish in the wind. They only have a short window to grow and fruit if they do get past the seedling stage. So I'm hoping to give them a better start, and an earlier one. I was hoping to design my tunnel so that the cover could be raised or slid back from the southeast side in the thriving moments of the year, leaving the cover pushed back and still blocking the windward side... but this is not a good idea if the vinyl will become toast in that position.
I used row cover as a shade cloth in my greenhouse last summer, after a week of scorching UV making my tomatoes unhappy. No sooner got it up, then we had the July from hell, a month of constant rain and cold. They would have done better without the row cover, it blocked too much light in those conditions.... Trying to second guess the weather here is a tricky business! |
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