Broad beans grow very well at Ashbrook and can produce a large crop; they are fairly frost hardy and very suitable for a first sowing when catch cropping.
A very hardy variety such as Aquadulce can be sown in the ground in autumn about Guy Fawkes Day with the seed sown in double rows, 22cm (9”) apart each way with 120cm (4’) between double rows. In a mild winter this works well however a cold winter, mice and birds can do severe damage to the seed and young plants. Seed of later varieties can be sown directly in the ground as above.
One particularly damaging pest to young broad bean plants is bean/pea weevil which normally appears about mid-April. This pest has been on our site for many years but does seem to be getting worse, it affects young plants of both broad beans and peas; above ground the damage starts with small semi-circular notches chewed out of leaves, below ground the larvae are reputed to feed on the plant roots. Affected plants don’t grow as they should and are debilitated resulting in a significantly reduced crop, occasionally complete plants can be destroyed. The weevils are about 5mm (1/4”) long, brown coloured and if disturbed easily fall off foliage. Birds don’t seem to predate them however some gardeners find they can catch these pests in their fingers and deal with them as they see fit. Try this by all means however there are far too many of them and I don’t find this a practical solution. Directly sown seed put directly in the ground during April and May is particularly badly affected. There are however a number of solutions: –
- Seed of Aquadulce can be sown in the ground in November as mentioned above and provided the winter is not too harsh the plants should be sufficiently developed and strong enough to withstand attack by the time the pest appears.
- Alternatively start off seed during January or the first half of February in 75 or 100mm pots, grow on in a greenhouse or cold frame so as to develop a strong, stocky, robust plant with a pot full of root, harden off and plant out into prepared ground with cloche or windbreak protection in February or March. To prevent mice damage it might be worth covering seed in pots even in a greenhouse with suitable netting. I have tried starting off broad beans in toilet rolls which although good for root crops such as carrot and parsnip don’t allow the roots of broad beans to break out quickly enough, also cell trays (modules) such as P24s generally are not big enough to allow sufficient volume of compost and good early root development. Strong rooted pot grown plants put into fertile ground and encouraged to grow quickly should result in the plant being able to withstand and outgrow weevil.
- Don’t let plants struggle through lack of water, keep roots of young transplants moist.
- If all else fails and the plants are still obviously suffering from weevil attack this is one of the very few occasions when some might want to consider reaching for the bottle. Applying a liquid insecticide suitable for use on vegetables via a watering can fitted with a fine rose so both foliage and stem are treated will not eradicate the whole problem but should knock the pest back sufficiently to allow a short respite for the young plants to grow away strong enough to withstand another attack. Application at dusk so the leaves are wet for longer when more of the pests emerge seems to have the best effect.
Because Ashbrook is prone to strong cold winds temporary protection with insect mesh or a screen of Rockalene or debris netting will help young plants and encourage strong early growth. Any covering should be removed when blossom appears to allow clear access for pollination.
Broad beans can grow tall and hold a heavy crop so bamboo canes along the outside of the rows supporting a couple of horizontal lines of string should prevent the plants falling over in strong wind.
Blossom appears very soon however keep an eye out for broad bean aphids (black fly) which appears most years, often almost overnight. They colonise the soft growing tip and if not dealt with promptly will smother most of plant and ruin the crop very quickly. Ladybirds might consume a few but are incapable of keeping the outbreak under control. Pinching out the top 5cm (2”) of the growing tip after a reasonable amount of blossom has appeared so the top of the plant toughens before the aphids arrive should prevent or reduce the infestation. Removing the growing tip will also allow the plant to put its energy into producing a better crop.
As the crop develops keep the plant roots moist to ensure the pods fill out with succulent beans. Feel the pods frequently and open the odd one to check how they are filling, the beans are at their best when still young, aim to pick the crop while still tender and before tough skins are formed.
Use what you can while they are fresh and freeze the rest. Back in the 1970s, blanching was recommended before freezing. Some find this spoils the crop and these days our surplus is podded, put straight into polythene bags and into the freezer within an hour or two of picking without blanching, we find they freeze far better this way. Fruit is frozen as it is so why blanch vegetables, the choice is yours?
An early crop of broad beans should be finished and out of the ground about the end of June. If once the beans are picked the ground is cleared, scratched with a three-prong cultivator or lightly forked, revitalised with a dressing of general fertiliser such as blood fish and bone or Growmore a catch crop can be planted. Suitable follow-on crops are leeks, squash, sweet corn, lettuce, calabrese or winter brassicas, these can be grown on for several weeks elsewhere ready to be transplanted early in July. Seed of beetroot, carrot, lettuce and turnip can be sown directly in the ground although with diminishing daylength I find 15th July is the last date for sowing these crops outdoors if they are to produce a worthwhile crop in the same year.
Suggested broad bean varieties that have produced well on our site:
- Aquadulce for October, November and January sowing.
- Imperial Green Longpod for February sowing, a strong grower.
- Bunyards Exhibition, an old variety for February/March sowing, another strong grower.
- The Sutton – a dwarf, more bush variety suitable for raised beds and suitable for February/March sowing.
Ashbrook Allotments 