How to Grow Beans in Liquid

Drill a 3/8 inch hole in the side of the square plastic tub, 3 inches from the top.

Cut the Styrofoam to fit into the top of the tub, using a utility knife.

Draw a line diagonally from corner to corner on the Styrofoam. Draw a second line diagonally from the other corners, making an "X" on the Styrofoam. Cut a 2-inch notch out of each corner.

Center an upside-down foam cup in each of the four sections marked on the Styrofoam and draw a circle slightly smaller than the top of the cup. Cut the circles out with a utility knife.

Cut at least two 1/2-inch-diameter holes in the bottom of each foam cup. Line each cup with a layer of cheesecloth, allowing it to extend up and out of the cups. Place the cups into the holes in the Styrofoam. Place the Styrofoam into the tub.

Rinse the perlite thoroughly. Perlite is dusty; avoid breathing the dust. Add equal parts of vermiculite and peat moss. Mix well, adding more water if necessary. Fill each cup with the planting mixture.

Push bamboo poles into the notched corners at an angle. Pull the tops together and tie them with twine, centering the pyramid in the planter. Continue wrapping the twine around the poles, all the way to the bottom. Tie them in a knot and cut off the excess twine.

Mix the hydroponic fertilizer according to the manufacturer's directions. Gently pour it into the planter until the solution dribbles out of the hole in the side of the tub. Add more fertilizer weekly to keep the roots of the beans in the hydroponic solution.

Plant two beans in each foam cup, covering them with 1 inch of planting mix. Mist with water regularly to keep the seeds moist. Beans will sprout within eight to 10 days when kept at 70 to 80 degrees Fahrenheit. As the bean plants grow, the roots will extend through the cheesecloth, out of the cups and into the hydroponic solution.

Hang the grow light above the planter, 2 to 4 inches above the planting mix. Put the grow light on a timer so the green beans receive at least 8 to 10 hours of light daily. Move the grow light up as the beans climb up the bamboo trellis.

Monitor the green beans for pests such as fungus gnats and Mexican bean beetles.

Harvest the green beans when the pods are firm and elongated but before the seeds are fully developed. Snip the pods off the plant with scissors to avoid damaging the vines. Removing the pods before the beans are fully mature encourages the vine to continue producing blossoms and beans.