The first step in getting peas started is to build a trellis. You can even build a trellis for southern peas although they grow mostly in bush form. There's been recent research that shows peas grow more fruit if they're supported. Results show a 30-60 percent higher yield, or amount of fruit grown, on trellised plants.
A trellis doesn't have to be expensive or fancy, just sturdy and easy to use. You can build a simple trellis out of recycled materials. To build a pea trellis, use three recycled 2x4's. The first step is to make an angle cut on the ends of two of the boards. To do this, use a circular or hand saw to cut off the square edges, leaving a point at the bottom. Position the first board at one end of the bed, placing it in the center of the bed. Place the other board 6' away and hammer it in with a sledgehammer. The board should go 2'-3' into the ground. Next hammer the other board in place. If your dirt is very hard, you can dig a 2'-3' deep hole, place the board in the hole and back-fill it with dirt to secure the board.
Once both of your support boards are in place nail the third 2x4 across the top of the two boards set in the ground. Use galvanized 3" nails to hold them securely in place. With the outer frame complete, begin assembling the string supports. Nail 1.5" galvanized flathead roofing nails along one side of each of the three boards. Space the nails approximately 10" apart. Nail them so that about ¼" of the nail sticks out, leaving space behind the head to attach the string.
Use a ball of garden twine to create netting on the trellis. Begin at the bottom nail and tie off one end of the string. Pull the string across to the second board and loop it around the corresponding nail. Go directly up to the next nail, loop the string around it and then pulled it back to the first board. Continue looping and pulling the string until you lace it up the entire span of the trellis. Tie the string securely to the last nail.
The final step is to install the vertical trellis strings. Start at the top by attaching the string to a nail. Drop the string straight down. Tie it to a horizontal string with a single knot each time the strings cross. At the bottom horizontal string, tie off the string and then cut it off.
Complete the trellis by repeating this process for all of the vertical strings. Work your way across the trellis and a grid pattern will take shape. Make sure each string is secure along the bottom horizontal line.