Cut nine 4 x 4-inch squares of each material so that you have three for each test: water resistance, wear resistance and stain resistance. Mark the squares of each group with the same number in permanent marker so that you know which square belongs to which fabric.
Test for water resistance and drying time. Soak each of the squares (three of each type) in water for 30 seconds, and then lay them on a paper towel to dry. Blot each square with a paper towel for five seconds every 10 minutes to see if any water comes off on the paper towel. The fabric is dry when no water comes off on the towel. Write down how long it takes each one to dry. If they all dry in less than 10 minutes, restart the experiment and do the blot test every 30 seconds.
Test for wear and tear. Rub across each fabric piece 10 times with a wire hairbrush. Rank them by how much wear they show. The fabric that performs best in this test will have the least number of fibers pulled up or torn by the hairbrush. If all fabric pieces are unaffected by the wire hairbrush, try lightly rubbing them with a cheese grater and rank them once again by the number of fibers that are pulled up or ripped.
Test for stain resistance. Take a fresh piece of grass for each square of material and rub it vigorously against the fabric for 30 seconds. Let all pieces set overnight, and then wash them on the light cycle in the washing machine, with normal detergent. Do not hand-wash them because it's harder to give them the same amount of scrubbing by hand. Rank them by how much stain they have left after they are washed. The darker the color, the lower you should rank the material.
The best fabric for outdoor use will be the one that averages the best for all three tests. Give each fabric type one point for each test that they did the best on. The one with the most points is the best for outdoor use overall. Include in your results which fabric is best for water resistance, which fabric is best for wear and tear, which fabric is best for stain resistance and which fabric is best overall.