Clear packing tape sounds like it would work. Or, they sell kits for repairing those plastic above-ground swimming pools. Not sure where, but I'd call around. Perhaps Watsons?

We used clear silicone to repair some hail damage to the 6-mil poly on our greenhouse years ago. It held up very well - for 7 years, until we replaced the plastic this spring when moving the greenhouse.

Fire..., I was wondering if tape would peel off from the forces of weather. I've never heard of Watsons--is it a store near where you live?

AB..., What 'format' was the silicone in, tape, caulk, something else?

It was silicone caulking - sorry, I had that in mind but I see I didn't actually say it!

Hello,

I want to require your help, please, with a similar problem:
we are putting the plastic cover on the metallique structure. And when we have to fix it at the sides on the bottom in these special rails, the plastic was cut along. How we have to fix them without cutting the plastic??
Can anyone answer me very rapidly??

Thank you very much in advance!