Sometimes nature provides the means. Sometimes man-made detritus can be repurposed to meet our needs. For example, prickly vines provide effective garden protection and discarded utensils do nicely to mark crop rows.
Pumpkin Vine Fence
For several years we lost many of our garden plants to groundhogs and rabbits. Then a friend suggested I plant the outer border of the whole garden in pumpkins. The vines form a prickly "fence" that the animals just will not go through (I wear long pants myself, to climb over). The only problem was what to do with all those pumpkins in the fall, and I solved that by giving them to needy families who use them for baking casseroles and pies and for making Halloween jack-o'-lanterns for their children.
North Webster, Indiana
Plastic Row Markers
I collect discarded plastic forks and spoons and use them as row markers. After washing them, I just write the name of the planted flower or vegetable on the handle with a permanent marker, and stick the eating end into the soil. This practice not only saves money, it's one more way to recycle.
Santa Barbara, California