Building a rain shelter, what type of tarp to use?

Figured I would start a separate topic for this.

Im playing around with some ideas for building a rain shelter to use over my plants later in the season. Basically I'm going to build some sort of basic frame out of wood, or possibly attached to the side of the house that I can string some rope across and then cover everything with a tarp if/when we get some rain. I'll leave two sides open for ventilation.

I got the idea from some of the rain-fly/lean-to type shelters we used to build while camping.

I guess my question is, what type of tarp to use for the roof? I'll need something roughly 30' by 40'.

i first looked for clear greenhouse tarps. Turns out they're really expensive. White ones aren't too bad, and I think it would still let a decent amount of light through.

but a blue tarp from Home Depot would be even cheaper. Do you guys thing the blue would block too much light? Remember this will only used short term in October, possibly during late September if we get an early storm. Depending on the weather it could be up for a few days, or maybe a week. I would take it down when the weather is dry.

Thanks!

i'd look into some clear 6mm plastic sheeting it should cost you less than $100 to cover that 30'x40'

Check out the carport greenhouse thread.