srcog screen

farm fencing 2x2 square holes made from galvenized wire is the best imo.

string will work, if you can keep it nice and tight,
have you made the screen frame with adjustable hight legs ?
keep the screen low to start with as it's easy to move them up but not so easy to move them down.

middy

 

I made mine with pvc pipe and threaded weed whacker line through it 2" apart

 

go to the local hardware shop, figure out how many feet you would need to make a square, buy that.

buy balers twine to, or some sort of heavy-ish string.

also buy 4 elbow joints, that fit the inner diameter of your pvc piping.

at home:

-drill along the pipe every 2" on all pieces of pipe.
-connect into square using elbows. (its ok if its slightly floppy at this point)
-weave the twine/string through. use an "over under" pattern when doing the second half of the weaving.(pull the string good and tight before you tie it off, if done right it will pull your screen into a rigid position.

voila

 

the way i built mine was for a 2x2 tent...I made my pieces 2x2 but did a dry run with out the screen weaved. this way i could cut it out how i wanted so that put in place it would have the armpit of the corners on the outside of the tent poles.

 

Depends, is the 3 foot tall lanky an bendy? Could you mash the screen down that far? It depends on how much height you have in your grow space. You can also just raise the other plants.