Peter Cundall: How to fill your garden full of beans
Not only are broadbeans super easy to grow and nutritious, they are also exceptionally good for increasing soil fertility, writes PETER CUNDALL
I’ve long suspected that the reason why broadbeans have such short harvesting periods is due to day-length and cool, wet conditions that frustrates pollinating bees. No matter when we sow seeds, autumn or winter, most broadbean plants only begin forming pods around the same time, usually during October.
What makes these plants so remarkable, is an astonishing ability to keep growing, even if regularly frozen solid during night-time frosts. This is why they are such a valuable food crop, growing through the coldest winter months and giving us a nutritious harvest of tasty beans at a time when many other fresh vegetables are relatively scarce.
There is another great benefit from growing broadbeans in our own vegetable patches. These extra-vigorous legumes have powerful, widespreading roots, making them exceptionally valuable for increasing soil fertility, even while growing and cropping.
They do this by fixing and locking-in nitrogen, extracted from soil atmosphere.
It’s worth digging out a broadbean plant and washing the soil from its roots just to see how it is stored. Once soil is removed, great, clinging clusters of pale nodules become exposed. These lumpy nodules are forms of nitrogen, one of the most significant elements needed by most plants, especially leafy vegetables such as silverbeet, lettuces and brassicas.
Broadbean plants have simple needs, which is why they are easily grown and highly-productive, despite little effort on our part. They need an open, sunny bed and well-drained soil and little else. The plants appreciate a sweet soil, so sprinkle a good handful of lime over every square metre of surface and rake in.
I’ve never bothered using fertilisers when growing broadbeans, even in fairly impoverished soils. Sometimes it may be
Broadbean plants have simple needs, which is why they are easily grown and highly-productive, despite little effort on our part
necessary to sprinkle sulphate of potash alongside broadbean plants if growing in over-rich conditions.
Potash firms leaves and stems, making them less vulnerable to attacks from black aphids. Most broadbean plants don’t need watering during winter and early spring because most Tasmanian soils contain plenty of moisture during cooler parts of the year. In low rainfall districts the plants may need a watering during September and October.
Push the big seeds into cultivated soil down to the second finger joint and space them about 10cm apart. These are big plants and even the so-called ‘dwarf’ varieties with still grow to a height of 1.5m or more. Most seedlings are up and moving in a couple of weeks and never look back.
The big mistake is to sow seeds too close, because this encourages fungal problems especially broadbean rust, through poor air circulation because of congestion.
Many begin flowering in late August or even earlier, but few pods will form until the bees start to get busy. However, when the first pods begin to form, most plants gradually become top-heavy and this can be a real problem if blown over. When this occurs, the stems bend and become kinked, causing growth to stop and crops to fail.
It’s a simple job to surround a broadbean patch with wooden garden stakes and stretch strong twine between them, also criss-crossing through the plants. Some people obtain an earlier harvest of small, extra-young pods and cook them whole, but from my experience, flavour is insipid.
However, if the beans are harvested while still small – a little bigger than peas – they are incredibly sweet and delicious eaten raw.
Children love them so should be shown how to harvest the young pods by pulling them sharply downwards rather than trying to drag them off the plants.
When we purchase broadbean seeds, there are usually far too many in packets. Don’t waste them, scatter all surplus – and last year’s left-over seeds - over any vacant beds and rake them in. They make fantastic green manure if smashed down and dug in when about knee-high.