Re: what are the fastest growing bean seeds

It will depend on how you measure the speed of growth, the cultivars (cultivated
varieties) you are comparing and the environment. Speed of growth can be
measured in several ways, including increase in height, gain in fresh weight and
time to maturation of the bean crop. Climbing or pole types grow taller than
bush type beans so a climbing lima bean might grow faster in height than a bush
type of kidney bean and vice versa. If you are growing lima beans and kidney
beans, you can determine for yourself, which of the two cultivars you have grows
the fastest under your conditions.

If you buy packets of garden seeds, the cropping time in days is usually printed
on the package. 

Kidney beans are certain cultivars of Phaseolus vulgaris. Lima bean is Phaseolus
lunatus. 

The first website says broad bean 'Express' is the fastest maturing cultivar of
broad bean, but there are many types of beans.

References


Thompson and Morgan bean seeds


Lima bean production guide


Dry edible beans