27 August 2019

Bountiful beans

Ditch baked beans for these tasty alternatives this August.

By Héléna Dove and Ellen McHale

Kitchen Garden

At an impressive height of three metres, you can't miss our huge runner bean plants (Phaseolus coccineus) in the Kitchen Garden. 

Full of beans 

Originating in Mexico, this crop appeared in Europe in the mid 17th century, and was originally grown as an ornamental plant.

Like many other vegetables, runner beans have been bred over time to produce a bountiful crop for a longer period. 

They used to be a short day plant, which means the plant wouldn’t flower until the nights were more than ten hours long. In the UK this only occurs in September, so the plants would have only had a month to produce beans until the winter frost stopped them in their tracks. 

Luckily for us bean-lovers, this trait has been bred out of the plant. It's now a day-neutral crop that can flower regardless of the amount of daylight it receives, producing beans for a much longer period. 

Did you know?

Although grown for its seeds and seedpods, runner bean leaves and flowers are also edible. 

Protective pots 

At Kew, we sow runner beans at the end of April or the beginning of May (around two weeks before the last frost is forecast).

Runner beans aren't very hardy and won't tolerate temperatures below 5˚C. To protect them we sow them into pots to keep them cosy in the cold. 

They need very fertile soil as they’re heavy feeders, and they need sturdy supports that they can twine around and grow tall. 

Runner beans, Kitchen Garden RBG Kew
Runner beans, Kitchen Garden RBG Kew

Plant pals 

Companion planting is when different plants that enhance each other's growth are planted next to each other.

Beans are pollinated by bees and other flying insects, so growing plants nearby that attract pollinators gives them a helping hand. 

Beans like to keep their roots shady and moist, so planting lettuce underneath them works well as this stops transpiration of water and provides shade.

Kitchen Garden
Kitchen Garden, Andrew McRobb © RBG Kew

Resilient varieties in a changing climate 

This year we're growing the cultivar ‘White Lady’ - look out for its pretty pure white flowers.

This cultivar withstands drier conditions much better than other varieties which is useful in the hotter summers we've been experiencing. In the future, we'll rely on these hardier vegetables more and more as the climate becomes unpredictable. 

We've also growing the cultivar ‘Celebration’ which has beautiful salmon pink flowers, and 'Hestia' which is a dwarf runner bean that grows to 45cm high. This is ideal for growing in a large pot and is perfect for balconies or small gardens. 

Runner beans in the Kitchen Garden
Runner beans, Kitchen Garden RBG Kew
Lettuce, Kitchen Garden

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