Projects on my mind

I have a neat idea, and I'd like some technical support, please.

Psuedo Greenhouse.

There's a nice porch on my house that runs the entire width of the front (See Photo). We don't use much of it, and I'd love to section off maybe 1/4 of it, on the south side, and make it into a very very low-tech greenhouse. The south side of the house runs roughly parallel with the driveway. So what we're talking about here is the area from the garbage can over to halfway between the first two iron pillars from the right.

I'm thinking right now that I could just attach vinyl sheeting from the overhang to the floor alongside the south and west edges (using a staple gun, maybe?), and then put up a tension rod and a heavy duty shower curtain. If I use a tension rod and shower curtain method, it would allow easy access via the porch. I'm not sure if that description made sense.

My excellent tape measure has gone temporarily missing, though, and it's driving me bonkers. I can't measure! The depth of the porch is about 6 feet (72 inches, or approx 2 meters), and the height to the bottom of the overhang looks about 8 feet.

Here are the basic questions I have for you. Keep in mind that I rent.

1. How do I effectively deal with the wind? I don't want strong gusts to blow everything down. This would be more an issue with the south and west sides than the tension rod side. Something I just considered would be attaching hooks into the overhang and use shower curtains there, too. That way they'd detach easily, so that if we have high winds I can just take them down. The added bonus to this possibility would be that I could buy fabric shower curtains to put up in the heat of the summer, providing both shade and privacy from the street.
2. How could I anchor the sheeting on the bottom? I don't want the bottom to be flapping around, but neither do I want to increase the stability so much that the sheeting will act like a sail. (See above re: wind.)
   
3. What other issues am I not taking into consideration? I'm not much of a planner, and I do want to avoid having to re-do the entire project. For instance, when I laid out my raised beds, I overestimated the amount of sun they got. One of my next major projects may be moving them (ugh!) a ways down into the driveway, which is much sunnier.
   

In other news, Project Front Yard is coming along nicely. That big ole mound of woodchips you can see if the photo has been spread over an expanse of cardboard, which should be killing the Bermuda grass in an excellent way. The entire south side of the front yard is now mulched, and the north side has a pleasing curved bed. As soon as I get more cardboard, I plan to also kill/mulch along the south side of the house. There's some nasty tall grass that I can't seem to keep under control.

Oh, another question: What your opinion about Round Up? I have a section in the backyard that is extremely overrun with blackberries and invasive honeysuckle. There's a stump under it all, so I can't mow over it. Will the Round Up leach into the soil and kill other stuff, or is it a valid way to clear the area?

Whew. OK, thanks.