String beans that grow vertically, up to 6-feet high, are called pole beans. The beans could sprawl on the ground but their tendency is to wrap themselves around a support and climb. Pole beans take longer to get to harvest but produce more beans over a longer period of time than bush beans. String beans come in yellow, green, purple and mottled, all tasting very similarly. Set up a temporary string trellis for your string beans.
Drill a hole on both ends of each piece of 2-by-4 through the thinner width of the wood (the 2-inch width). The hole should be at least 1 inch away from the edge of the end of the wood, 1 inch from the sides of the wood and at least 1 inch deep. The diameter of the hole should be slightly bigger than the diameter of the rebar. The drilled hole should not go all the way through the wood.
Drill additional holes spaced 6 inches apart and 1/4-inch diameter through the thinner width of the wood (the 2-inch side) down the length of each piece of wood. If the wood is 6 feet long there will be 12, 1/4-inch holes and two holes the diameter of the rebar.
Cut the string into 7-feet pieces. Mark each length of string 6 inches from the end. Place the two pieces of wood 6 feet apart on the ground. Thread the first piece of string through the first holes of each piece of wood. Loop the string around the wood and tie securely. The mark should be on the inside of the wood. This way each length of string between the wood is 6-feet long. Thread another piece of string through the second holes on each piece of wood. Continue threading the string through succeeding holes in each piece of wood.
Dig a 12-inch deep, 4-inch wide trench in the garden between the bean rows or where the beans will be planted. Place one 2-by-4 in the trench. Lay the other one on the ground close by. Burying the wood stabilizes the trellis.
Place the rebar in each side of the 2-by-4 in the trench. Bury the wood by filling in the trench.
Place the second piece of wood on top of the rebars by fitting the rebars in the drilled holes.
Place the second piece of wood on top of the rebars by fitting the rebars in the drilled holes. The string is now stretched between the two pieces of wood and ready for the string beans to climb.