Growing Pole Beans in Containers
Pole beans are great balcony garden plants because they grow on long vines making them perfect for vertical gardening. Kentucky Wonder are my favourite Pole Beans. I've had no problems getting them to flower and set loads of fruit. Vines easily grow over 12 feet with beans reaching up to 8 inches long when grown in a container.
The best container for planting pole beans on the balcony is a long container: 2-3 feet long, 10 inches wide and 10 inches deep. Use a self-watering container if you have one available. The large leaves transpire lots on hot breezy days and the self watering container helps keep the plants continuously hydrated.
Young pole bean plants ready to start climbing.
I get two or three harvests like this from 14 or 15 plants.
I don't do anything special to the potting soil. The usual mix will do. But you will need to add fertilizer constantly as the season progresses. I always end up cheating and using a water soluble in-organic fertilizer throughout the growing season for pole beans. The plants get big and suck up lots of nutrients. Beans, like all legumes, are nitrogen fixers which means they have the ability to pull nitrogen from the atmosphere. But don't let that fool you into a false sense of nutrient security. These plants needs lots of nitrogen and they will not thrive in a container without additional nutrients, including nitrogen.
Beans are easy to grow. Don't start them when it's too cold outside. I find they don't tolerate the cold. Chilly winds easily damage young bean plants. Seed them directly into their container in a single row along the container with approximately 2 to 3 inches of spacing. More space is better and if you can, give them more than 4 inches of separation. I tend to overcrowd my plants: a bad habit that's easy to fall into when you don't have as much space as you'd like to have.
In a garden that gets lots of overhead sunlight, pole beans can be planted in a hill beneath a teepee like structure. The beans will grow up the structure and be bathed in sunlight from above. But on my balcony, the sunlight only comes in from one side so a trellis works best.
I usually build a trellis (at the last minute) from from bamboo poles. It's never pretty but it works. I put two long vertical poles at either end of the container, with horizontal poles across the bottom, middle and top. String, wire, cable ties... even duct tape is used to hold the trellis poles together. I then tie lengths of heavy cord at the top and bottom of the structure wherever I planted a bean seed. As the vines grow they will climb the cords to the top of the trellis. My uprights usually extend 6 feet above the container. Sometimes I duct tape smaller poles together to make longer poles. To provide stability for the upright poles I drill holes through the sides of the container on both sides of the poles, then use wire or a cable tie to secure the pole to the wall of the container.
Once the vines start climbing the trellis they grow fast and within a couple of weeks they should be up to the top of the trellis. You can pinch off the tops of the vines to encourage branching further down. Or just snip the ends with a pair of scissors. I like to prune off some of the vines that shoot off from the main vines if they look skinny and weak so they don't steal nutrients from flowers and fruit. Especially if those vines project out the back of the trellis where they won't see much sunlight.
Pole beans having just reached the top of their trellis. These will fill out much more before the season is over.
The beans on my plants reach 6 to 8 inches in length. I like to pick them before they get too mature.
As the vines grow and fill out, you'll end up with a wall of green. Watch the leaves for signs of nutrient deficiencies: yellowing or dead spots. And be on the look-out for spider mites. One advantage to having your plants up on a trellis is that you can get behind them to spray the backs of the leaves and blow away any spider mite colonies or mildew that might take hold. Also watch for leaves wilting in the heat as the summer progresses. Having all that plant mass growing out of a single container means you'll need to water it regularly.
Within a month of sprouting you should start to see flowers on your plants. The flowers are perfect, which means they have both male and female components and can self-pollinate. All it takes is a good breeze to shake things up a bit. Each flower should turn into a bean if conditions are right. Most pole bean plants produce rather long beans. I like to pick mine before they get too big. Once the seeds start to bulge inside the pod, that's too late for me. I like them tender. As you pick the beans, the plants will be encouraged to produce more until they eventually give up for the season.