Grow bags save space and allow urban gardeners to create small, personalised growing areas. The prospect of growing a notoriously prolific vine such as that of the runner bean plant in a grow bag might befuddle a novice gardener. It's easier than you think to adapt a grow bag and growing space to the requirements of runner beans and, with a few simple materials, you can create an environment that will allow runner beans to thrive.
Sow runner beans in early spring.
Fill grow bags with potting soil. Poke planting holes to a depth of 5 cm (2 inches). Space holes 7.5 cm (3 inches) apart. Place two beans into each hole. Sprinkle potting soil over the grow bag's surface to fill the holes and cover the seeds. Moisten the soil until water drains from the bag. Keep the bag's soil evenly moist, watering at least twice daily until germination (sprouting) occurs.
Remove all but the strongest seedling in the planting hole when the seedlings reach a height of 7.5 cm (3 inches). Thin the seedlings by pinching them off the stem near soil level.
Build supports for the runner bean vines. Run twine from the grow bag to the top of a fence, wall or other elevated point. Place the grow bags near a fence, wall or stair railing.
Create holes around the half of the bag's circumference that face a wall or fence, using a hole-punch. Punch holes approximately 2.5 cm (1 inch) below the bag's edge.
Run an end of the twine through a hole. Secure it in place with a knot. Pull the twine to the top of a fence or wall. Tie the twine at the top of a fence or wall, such as through a link on a chain link fence. Cut the twine, leaving enough excess twine to create a knot. Pull the twine taut and tie it to a wall or fence.
Tie twine from each of the bag's holes to the top of the fence or wall. Encourage the vines to climb the twine as the plants mature.
Substitute galvanised or rustproof wire for twine to make a long lasting, weather proof support system.
Install concrete anchors and screws on block and brick walls to create an anchor point for your twine.
A rule of thumb for germinating seeds -- when the soil's surface begins to show signs of drying, such as a change in colour, it is time to water.
The runner bean is a cold-season crop.