How to Grow Sweet Pea From Seed: Nick, Soak, Sow by October
Sweet pea is the scented climbing flower of a plains winter, and it is not food. How to grow sweet pea in one paragraph: nick and soak the seed, sow by the end of October straight into a deep pot, give it netting to climb, full sun, and pick flowers every couple of days so it keeps blooming from about January into March. The seeds and pods look like matar but are poisonous, which is the first thing every family with children should know.
Quick facts
- What it is: Lathyrus odoratus, a cool season annual climber
- Sow: October in the plains; aim to finish by month end
- Pot: at least 25 to 30 cm deep (10 to 12 inches), 15 litres or more
- Support: netting or strings 1.5 to 2 m tall for climbing types
- Sun: full winter sun
- Flowers: about January to March in Lahore and Delhi
- Safety: seeds and pods are poisonous; never mix with edible peas
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Sweet pea is not matar: the safety point first
NC State Extension lists sweet pea seeds as poisonous, with the pods inedible, and warns not to plant sweet peas near edible peas. The illness linked to eating Lathyrus seed is called lathyrism. The real risk at home is a mix up: a child shelling “peas” from the flower pot, or saved sweet pea seed ending up in the same jar as matar seed. Label everything, grow them apart from vegetables, and teach children that the flower peas are for smelling only. If you want edible peas, our guide to growing matar in pots covers them. For a wider list of risky home plants, see poisonous plants for kids and pets.
Seed or nursery seedlings?
Seed, for this flower. Sweet peas grow a long root and resent being moved, so a nursery seedling in a tiny bag often stalls. Seed is large, easy to handle and sprouts within one to two weeks once soaked. Sow directly in the final pot.
When to sow sweet pea seeds in Pakistan
| Zone | Sow | Bloom |
|---|---|---|
| Karachi | Late October to mid November | January to February |
| Multan, Sukkur, Bahawalpur | October | January to early March |
| Lahore, Faisalabad, Delhi | October | January to March |
| Islamabad, Peshawar | Late September to October | February to April |
| Hills | March to April | Summer |
The deadline matters. Plants sown in December are still small when March heat arrives, and flowering stops early. NC State notes sweet pea struggles in hot, humid conditions, which describes the plains from April.
How to grow sweet pea from seed
- Nick: rub each hard seed once on a nail file or sandpaper, just through the dark coat on the side away from the eye, until a pale spot shows.
- Soak overnight in room temperature water. Swollen seeds are ready; sow any that stay hard after another nick.
- Prepare the pot: a deep pot with 2 parts soil, 1 part compost and 1 part sand. See our potting mix guide.
- Sow 2 to 3 cm deep, about 8 cm apart, six to eight seeds in a 30 cm pot.
- Water once and then only when the surface dries. Soggy soil rots the seed.
- Put up support now, before roots spread: a frame of bamboo with netting or strings.
- Pinch the tip when plants have three or four pairs of leaves. They branch and give more stems.
Picking is the fertiliser
Every sweet pea flower left on the plant becomes a pod, and once pods form the plant thinks its work is done. Cut a bunch for a jar every second day, even short stems. The more you pick, the more it flowers. Any pod you miss, snip it off and bin it, away from children.
Sweet pea care in pots
Water
Keep the soil evenly damp, never wet. That is every three or four days in November and once a week in a cold, foggy January; in late February sun, every second day. A deep watering is better than daily sips.
Cold
Sweet pea likes cool weather and handles light frost once established. Seedlings on a Punjab frost night are safer against a wall.
Feeding
Compost in the mix plus a monthly flowering feed (more potash than nitrogen) at half strength. As a legume it needs little nitrogen.
Climbing
Tendrils grab netting on their own, but guide young shoots in the first weeks. Dwarf, bushy varieties need only short twigs.
Why is my sweet pea not flowering?
| Sign | Cause | Fix |
|---|---|---|
| Lush vines, no buds | Too much nitrogen, or shade | Full sun; flowering feed |
| Flowers stop early | Pods left on | Pick every two days |
| Buds drop in March | Heat or dry soil | Water deeply; afternoon shade |
| White powder on leaves | Powdery mildew | Remove worst leaves, water the soil only |
| Twisted tips, sticky leaves | Aphids | Water jet, mild soap spray |
Is sweet pea annual or perennial?
The fragrant garden sweet pea, Lathyrus odoratus, is an annual: one season, then it dies. The so called everlasting pea (Lathyrus latifolius) is a different, perennial species with little scent, rarely sold here.
How to save sweet pea seeds
- Leave a few pods on the healthiest plant in March.
- Pick when the pods turn brown and dry, before they twist open.
- Shell onto paper, dry a week, and store in a jar clearly labelled “Sweet pea, POISONOUS, not for eating”.
- Keep the jar away from the kitchen and from vegetable seed.
Sweet pea seeds and pods are poisonous if eaten. If a child swallows seeds or pods, call your doctor or go to emergency care, even if they seem fine, and take a pod with you. Keep pots out of reach, bin pods you remove, and never store saved seed near food. The ASPCA lists the perennial sweet pea as toxic to horses; keep any garden animals away. For pests use water and soap first; with any chemical spray read the label, wear gloves and keep children and pets away until dry.
Sweet pea questions people ask
How long does sweet pea take to flower from seed?
About ten to twelve weeks. An October sowing usually flowers in January.
Should I soak sweet pea seeds before sowing?
Yes, after nicking the coat. Soaking overnight helps the hard seed take up water and sprout faster.
Are sweet peas poisonous?
The seeds and pods are, so they must never be eaten. The flowers are grown for scent and vases.
Can sweet peas grow in pots without support?
Dwarf types can. Climbing types need netting or strings, or they sprawl and rot.
Can I grow sweet peas in summer?
Not in the plains. They fail in heat. Only hill gardens can grow them in summer.
Why are my sweet pea leaves turning yellow?
Usually overwatering in cold weeks or a pot too small. Lower leaves also yellow naturally late in the season.
How deep should the pot be for sweet peas?
At least 25 to 30 cm deep. Their roots go down, and shallow pots dry out fast.
Do sweet peas need full sun?
Yes in winter. In late February and March, a little afternoon shade helps them last.
Can I grow sweet peas next to my matar?
Better not. Grow them apart so seeds and pods never get mixed.
More flower guides are in Phool aur Paudhe.