Runner beans are deep-rooted so it is advisable to dig the land more than a spade’s depth in order to make sure that the manure or compost is available to the roots. The manure should be added at a rate of a bucketful to every sq. yd. A popular method of digging the plot is to double dig to make sure that the fertilizer has reached the necessary depth, and then tread down firmly. After which fish manure with 10 percent potash content at 4 oz. (120g) to the sq. yd. should be raked in. The carbonate of lime can be applied as a surface dressing at 4 oz. (120g) to the sq. yd. unless the soil is chalky of course.
At sowing time, which should not be before the end of May in the north, though in the south it can be a couple of weeks earlier, rake in 2 oz. (60g) superphosphate and 1 oz. (30g) sulphate of potash to the sq.yd.
Runner bean seeds do not germinate in cold soil, so it is pointless sowing before the end of May in the north.
It is always good practise to space out the sowing so that there is a continuous supply rather than all the vegetables being ready at once. To make sure of a later picking make a second sowing in mid-June.
Generally, runner beans are grown to climb up netting or poles and remember they grow to over 6 ft so their climbing frame needs to be sturdy, each plant should produce a crop of approximately 4 lb of beans so it needs to have strength and stability. If the beans are to climb poles, push the poles or stout canes into the ground at least 9 in. (228mm) apart so that when they are drawn together they cross 6 in. from the top. Tie them together where they cross with horticulture twine making a kind of Tepee effect.
Sow the seeds at the base of the poles where they can be encouraged to climb up naturally. The seeds should be sown at a depth of 2 in. (50mm) and is preferably done with the aid of a dibber, making a hole to the desired depth and dropping a seed into it. It is also a good move to sow a few seeds at the outer circle so that any gaps can be filled in with the extra plants.
Methods of Growing
Runner beans, unlike many other crops, may be grown on the same plot of land year after year. They can be grown along wires between stout posts and to help them reach the wires vertical wires should be strung at 4 or 5 in. (101mm – 127mm) intervals, these will assist their climb. If netting is the preferred method is to be used then it is simply a matter of stretching the net between two posts until it is reasonably taut, the beans will be then able to scramble up unaided.
The beans do require plenty of water and it is a good idea to mulch the roots to help to retain moisture. Popular mulch for this purpose is grass cuttings scattered not more than 1/2 in. (12mm) around the base of the plants when they are in full growth, more may heat up the ground too much and burn the roots or damage the stems.
Pick the beans as soon as they are ready, this is before the seeds inside the pods begin to swell. Always a good thing to remember is that the more beans that are picked the greater the yield will be.