Broad beans sown in autumn crop weeks before spring sowings

In the UK you can sow broad beans outdoors from mid-October to late November, or from late February to late April. Autumn sowings with a hardy variety give the earliest crop, often picking from mid-May, and they’re usually past the worst of the blackfly before it arrives.

If your soil is cold and wet, sow indoors in pots from early February to early March and plant out from early March to early April.

Autumn or spring sowing

Broad beans are hardy to about -10 °C, which is why they can sit outside all winter. An autumn sowing germinates, makes a small plant a few centimetres tall, then waits. When the weather warms in spring it has roots in place and flowers weeks ahead of anything sown in March.

	Autumn sowing	Spring sowing
When	Mid-October to late November	Late February to late April outdoors
Variety	Aquadulce Claudia or another hardy type	Any, including The Sutton and longpods
First pods	From around mid-May	Early to mid-summer
Risks	Rot in waterlogged soil, mice, a very hard winter	Blackfly, dry spells at flowering

Aquadulce Claudia is the standard choice for autumn because it is especially hardy. Most other varieties are better sown in spring.

Autumn sowing isn’t for every garden. On heavy, waterlogged soil the seeds can rot before they come up. In that case, sow in deep pots or root trainers in a cold frame or cold greenhouse in late autumn or February, then plant out in spring.

The dates here are for a typical lowland garden in England or Wales, with a first frost around the end of October and a last frost around 20 April. In Scotland, the north of England and frost pockets, sow towards the start of the autumn window, or wait for spring. In the south-west, near the coast and in cities, late November sowings usually do fine.

How to sow

1. Choose a sunny spot that drains well. Broad beans don’t need rich soil, as they fix their own nitrogen.
2. Sow the seeds 5 cm deep and 20 cm apart.
3. Leave 45 cm between rows. Many growers sow a double row, two lines 20 cm apart with a wider path either side, so the plants hold each other up.
4. Sow a few extra at the end of the row to fill any gaps.
5. Water in if the soil is dry.

Mice dig up and eat bean seeds, especially in autumn. If you’ve lost sowings before, start them in pots off the ground instead.

Keep broad beans away from onions, garlic, shallots and leeks. They grow well alongside potatoes, carrots, lettuce and spinach.

Support

Broad beans grow to about a metre tall, and a full plant with pods on is top heavy. Spring winds or a heavy downpour will flatten them. Put a stout cane or stake at each corner of the row or block and run garden string around the outside at about 30 cm and again at 60 cm as they grow. Dwarf varieties such as The Sutton usually manage without.

Blackfly

Blackfly are the main problem with broad beans. They cluster on the soft growing tips in late spring and early summer, and a bad attack stops the plant cropping.

The best defence is to pinch out the top 8 to 10 cm of each stem once the first pods have set at the bottom of the plant. The aphids prefer the soft tip, and removing it also sends the plant’s energy into the pods. Autumn sowings are often tough enough by the time blackfly turn up that they shrug off a light attack. If a few colonies appear anyway, rub them off by hand or blast them with the hose.

Other problems

Chocolate spot. Brown spots on leaves and stems, worse in damp, crowded conditions. Give plants the full spacing and don’t overfeed with nitrogen. Mild cases don’t affect the crop much.

Poor pod set. Usually dry soil at flowering. Water well once the flowers open if the weather is dry.

Winter losses. A very cold, wet winter can kill some autumn-sown plants. Sow a few spares in pots to fill gaps in spring, or cover the row with fleece in a hard spell.

Picking

Broad beans are ready from mid-May to late July, depending on when you sowed. They take around 80 to 100 days, and a row keeps cropping for about six weeks. Pick pods when you can feel the beans inside but before the scar where each bean joins the pod turns dark. Younger beans are sweeter and don’t need double podding. Pick from the bottom up, and keep picking, as plants keep making pods while you do.

When the plants have finished, cut the stems at ground level and leave the roots in the soil, where they release nitrogen for the next crop. Brassicas such as cabbage or kale are a good follow-on.

VegLog can work these sowing dates out for your own town’s frost dates and remind you when the autumn window opens.