How to Grow Sem Phali: Why It Waits for Winter to Flower
Sem phali (hyacinth bean, lablab) is the bean you sow in the monsoon and pick in winter. If your plant is ten feet tall in October with no pods, that is normal: most desi sem waits for shorter days before it flowers.
That one fact explains most of the disappointment people have with it. Sow by August, give it something to climb, and be patient. The reward is a wall or railing hanging with purple or green pods from roughly November into February on the plains.
Quick facts for sem
- Sow: July to mid August on the plains; June to July in Islamabad and Peshawar.
- Pot: 25 to 40 litres (16 to 18 inch) per plant, or ground beside a wall.
- Sun: 6 hours or more.
- Climb: 3 to 6 metres if allowed; needs a strong net, railing or trellis.
- Germination: about 5 to 12 days.
- First pods: commonly 3 to 5 months after sowing, as days shorten.
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Why won’t my sem phali flower in summer?
Many sem varieties are short day plants. They flower when daylight drops below about 11 hours, which in Lahore or Delhi happens around late October. Sow in March and you get a huge leafy vine through summer that only starts flowering in autumn anyway, after taking up your roof for seven months. Sow in July or early August and it reaches flowering size right when the days turn.
A few modern varieties are day neutral and pod in about 70 to 90 days. If a seed packet says “early” or gives a short days figure, believe it and sow in spring; if it is desi seed from a neighbour’s vine, assume it is the winter type.
When to sow sem phali, city by city
| Zone | Sow | Pods roughly |
|---|---|---|
| Karachi, coastal | July to September | November to March |
| Multan, Sukkur, Bahawalpur | Mid July to mid August | November to January |
| Lahore, Faisalabad, Delhi | July to mid August | November to January, until frost |
| Islamabad, Peshawar | June to July | October to December |
| Hills | Not reliable | Frost arrives before pods |
Frost is the season’s end on the Punjab plains. A covered veranda or a south facing wall can buy a few extra weeks.
How do you plant sem phali seeds?
- Pick large, hard, unwrinkled seeds. Nick the seed coat lightly with a nail file on the side away from the white eye, or soak 6 to 8 hours.
- Fill a 16 to 18 inch pot with two parts soil, one part compost, one part cocopeat or sand (see the potting mix ratios).
- Sow 2 seeds, about 1 to 2 cm deep, at the base of the support. Keep the stronger seedling.
- Water gently and keep the surface just moist; in July heat that may mean daily.
- Guide the first tendrils onto the net by hand. After that it twines up on its own.
- Pinch the tip once at about 1 metre so it branches into two or three main stems.
Sem roots resent disturbance, so sow in place. The seed starting guide has the paper cup trick if you must start indoors.
How much water and fertiliser does sem need?
July and August: water deeply when the top 3 cm is dry, which may be daily in a pot, every few days in the ground. Never leave the pot in a puddle during the monsoon. September and October: the vine is huge and drinks a lot. November onward: water less, about twice a week in cool weather, never on frosty evenings.
Like lobia, sem is a legume and fixes some of its own nitrogen. Too much nitrogen is the second big reason for no pods. A handful of compost at sowing and another when buds appear in October is plenty. A potash rich feed (wood ash in small amounts, or a fruit and flower fertiliser at half label rate) at bud time helps pod set.
Keep last year’s vine
Sem is a short lived perennial. In Karachi, and on frost free walls elsewhere, cut the vine back to about knee height after the last pods in spring, water lightly through summer, and it reshoots in the monsoon, often flowering earlier than a fresh sowing.
Sem phali leaves turning yellow: what does it mean?
In the monsoon, yellow lower leaves usually mean waterlogged roots; check the drain hole. Yellow mottling with curling at the tips points to a virus carried by whiteflies, so pull out badly affected plants. In winter, a few older leaves yellowing as pods form is normal. If the whole vine looks pale and you never fed it, one handful of compost will do.
Common sem pests and first responses
- Aphids on buds and flower spikes: blast with water on consecutive mornings.
- Pod borers: look for small entry holes; pick and destroy affected pods.
- Whitefly: yellow sticky cards, and see whitefly and mealybug control.
Neem spray in the evening is the organic first step. For anything stronger, read the label, wear gloves and a mask, and wait the stated days before eating pods.
When are sem pods ready to pick?
Pick while the pods are flat, tender and the beans inside are just visible as small bumps. Fat, lumpy pods with leathery skins are past it for sabzi. Most vines start bearing three to five months after a monsoon sowing. Pick every two or three days and the vine keeps flowering until frost. For buying and cooking, see the sem and guar phali guide.
Raw sem beans and mature seeds contain natural compounds that can release cyanide; they must be cooked thoroughly, and dry seeds boiled with the water thrown away. Never let children chew raw pods or seeds from the vine. Young, well cooked pods are the normal food. A heavy vine on a railing catches wind, so tie it securely, and keep big pots off weak parapets.
Grow it or skip it?
Grow it if you have a wall, railing or roof net and you are sowing in July. It is close to the easiest winter vegetable for a lazy gardener: little feeding, few pests, a long picking season and a vine that shades a hot wall in late summer. Skip it if you only have a small balcony pot, or if you are in the hills where frost beats the flowers.
Sem phali growing questions
Why is my sem plant not flowering?
Most likely it is a short day variety waiting for autumn. Flowers usually start once daylight falls under about 11 hours, so a summer vine with no flowers is not a problem yet.
How long does sem phali take to grow?
From a July sowing, pods usually start in November, so about three to five months. Early, day neutral varieties can pod in 70 to 90 days.
How long do sem seeds take to germinate?
About 5 to 12 days in warm soil. Nicking the hard seed coat speeds it up.
Can I grow sem phali in a pot?
Yes, in a 16 to 18 inch pot with a tall support. A small pot gives a short vine and fewer pods.
What is the best month to sow sem in Pakistan?
July to mid August on the plains, June to July in Islamabad and Peshawar, and up to September in Karachi.
Will sem survive frost?
No, frost blackens leaves and ends the crop. Mild coastal winters let it keep going and even regrow next year.
Are the purple flowers edible?
They are used in some cuisines, but the main crop is the young pod. Cook anything you eat from this plant.
Is sem the same as guar phali?
No. Guar (cluster bean) is a different, upright summer plant. Sem is a climbing vine that pods in winter.
Sem kaise ugaye?
July ya August ke shuru mein deewar ya jaali ke paas beej boyein. Khaad kam dein aur sabr karein: phool aksar October ke baad aate hain jab din chhote hote hain.
More climbers and winter vegetables live in Kitchen Garden.