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Broad beans occupy the ground for a long time and do most of their work when nothing else is growing. An autumn sowing sits through winter as a small plant, restarts in early spring, flowers in mid spring and finishes by early summer. A spring sowing compresses the same sequence into about fourteen to sixteen weeks from sowing to first picking.
The reason to think of this crop as a schedule rather than a set of tasks is that almost every problem with it comes from doing the right thing at the wrong time. Pinching too early costs yield. Supporting too late means untangling a fallen row. Sowing too early in autumn produces plants that winter kills. The calendar below is written by stage rather than by month so it reads the same in either hemisphere.
| Stage | Trigger | What to do | What can go wrong |
|---|---|---|---|
| Autumn sowing | About six weeks before your first hard frost | Sow two inches (5 cm) deep in a staggered double row, net against mice and pigeons | Sown too early, plants get too big and soft for winter |
| Going into winter | First hard frost | Earth up two to three inches (5 to 8 cm), check drainage, remove row cover on mild days | Waterlogging and wind rock, which kill more plants than cold does |
| Spring restart | Soil rises past 45F (7C), plants visibly extending | Hoe the weeds, count survivors, fill gaps, put supports in now | Waiting until plants are tall makes stringing the row a fight |
| Spring sowing | As soon as the ground works and drains | Same depth and spacing. Expect first picking in fourteen to sixteen weeks | Sowing into cold saturated soil rots the seed |
| Flowering | First white and black flowers at the lower nodes | Start checking growing tips for aphids twice a week. Water in dry spells | Dry soil at flowering drops flowers and halves the crop |
| Pod set and pinching | Lowest three or four trusses hold pods an inch (2.5 cm) long | Pinch out four to six inches (10 to 15 cm) of soft tip from each stem and remove it from the plot | Pinching before pod set cuts real yield |
| Picking | Lowest pods plump, attachment scar still white | Pick every two or three days from the bottom up, two hands on every pod | Weekly picking gives starchy beans and a shorter season |
| Clearing | Top trusses picked | Cut tops at ground level, leave the roots in, plant a follow-on crop | A standing finished row breeds aphids and disease |
Supports: the job with the narrowest window
Broad beans do not climb and they do not need canes for every plant, but a laden row goes over in wind and pods lying on wet soil rot. The standard solution is a stake at each corner and every six feet (1.8 m) along the double row, with string run down both outsides at 12 inches (30 cm) and again at 24 inches (60 cm) as the plants grow.
Put the stakes and the first string in when the plants are about a foot (30 cm) tall, before the row closes up. Doing it later means threading string through tangled foliage and snapping stems, and doing it after the plants have already leaned means they never straighten. This is the one job on this crop where being a week early costs nothing and being a week late costs real work.
Add the second string as the plants pass two feet (60 cm). Dwarf types grown in exposed sites still benefit from a single low string, and beans in containers need a stake each because the rootball cannot anchor a three-foot plant.
- Stake at a foot (30 cm) of growth Drive stakes at both ends of the double row and every six feet (1.8 m) between. Push them in deep enough that they do not lever out when the row is heavy and wet.
- Run the first string at 12 inches (30 cm) One line down each outside of the double row, pulled taut. The two rows lean into the string from opposite sides and hold each other up.
- Add a second string at 24 inches (60 cm) Do this as the plants pass two feet. Two lines are enough for a full-height crop. A third at waist height only helps in very exposed sites.
- Retension after storms Walk the row after heavy weather and pull the strings tight again. Slack string lets the row lean progressively and it never comes back upright.
Water and feed, and when they actually matter
Broad beans need very little watering for most of their life. Deep roots and cool-season growth mean an established row on decent soil goes through spring without help. The exception is the period from first flower until the pods have filled, which is the only time water shortage directly costs you a crop. A dry spell then drops flowers and leaves you with half-empty pods.
Water thoroughly during flowering and pod fill if the top four inches (10 cm) of soil are dry, about a gallon per square foot (roughly 40 liters per square meter) once a week rather than a splash every day. Mulch between the rows after the soil has warmed to hold that water in.
Feeding is mostly a matter of restraint. This crop fixes its own nitrogen and responds to nitrogen fertilizer by producing tall, soft, aphid-attracting growth that falls over. Compost worked in before sowing is enough. On acid soil, lime is worth more than any feed, because it lifts the pH toward the 6.5 to 7.0 range this crop wants and reduces chocolate spot at the same time.
The pattern to remember is that broad beans are undemanding until they flower, and then briefly demanding. Everything you do for them concentrates into the few weeks between the first flower opening and the last pod filling.
Keeping the record that makes next year easier
Six dates turn this crop from guesswork into something you can plan: the sowing date, the plant height at the first hard frost, the spring restart, the first flower, the first picking and the last picking. Kept for each sowing separately, they let you compare an autumn row against a spring row directly and adjust by a fortnight in either direction with a reason.
Add two more notes. Write down where the bed was, because beans should not return to the same ground for three years. And write down the date you first saw aphids on the tips, because that is the number that decides whether autumn sowing is genuinely worth the winter risk where you garden.
None of this is elaborate. Eight short entries per sowing, made as they happen, will do more for next year's crop than any change of technique.