How to grow Sweet Pea
Updated October 2026
Sweet peas are fragrant, cool-season climbing flowers from the Mediterranean, grown on a trellis for armfuls of cut flowers in spring. They love cool, moist roots and full sun and fade once hot weather arrives, so they are sown in fall or winter where winters are mild and in very early spring in the North. Every part of the plant, including the seeds and pods, is poisonous, so they are for the vase only.
📖 Our full guide: How to Grow Sweet Pea
Not to be confused with: Sweet peas (Lathyrus odoratus) look like garden peas but are poisonous. Do not plant them where they could be mixed up with edible peas.
Where to plant
Grow sweet peas in full sun in rich, fertile, well-drained soil, ideally neutral to slightly alkaline; add lime to acid soil if a soil test calls for it. Dig in compost or aged manure well before sowing. They tolerate light frost and some shade, but struggle in hot, humid summers, when flowering stops and mildew takes over.
Do not plant sweet peas in the same spot in consecutive years, and keep them away from vegetable peas so the two are never confused.
- Florida, the Gulf South, Texas, the Desert Southwest and California: sow in fall (September to November) or winter for spring flowers.
- Mid-South, Mid-Atlantic and Southern Plains: sow in late winter to early spring as soon as the soil can be worked, or in fall where winters are mild; flowering ends in early summer heat.
- Northeast, Midwest, Mountain West, Northern Plains and the Pacific Northwest: sow outdoors as early in spring as the soil can be worked, or start in pots indoors in late winter for earlier flowers. The cool Pacific Northwest summer suits them especially well.
- Hawaii: sow in the cooler months, best at higher elevations. Alaska: sow in May; the cool summer gives a long season.
Choosing a variety
Choose by scent and habit. Old-fashioned and Spencer-type climbers grow 6 feet or more and are the most fragrant; dwarf and bush types suit pots and edging. In warm areas, heat-tolerant varieties such as Old Spice flower longer into late spring.
How to plant
- Set up a trellis, netting or canes before sowing.
- To help the hard seed absorb water, nick the seed coat gently with nail clippers or a nail file, avoiding the eye. Pale, white or wrinkled seeds should not be nicked. Many growers soak seed instead; sources disagree on soaking, so nicking is the safer method.
- Sow about 1 inch deep and 2 inches apart along the base of the support, then thin to about 6 inches. Seed germinates best in cool soil, about 55°F to 65°F, in two to three weeks.
- Pinch out the growing tip once seedlings have two or three pairs of leaves to encourage strong side shoots.
- Guide young shoots onto the support and mulch to keep the roots cool and moist.
Watering and feeding
Keep the soil evenly moist, especially once flowering begins. Dry, hot roots end flowering early.
Feed lightly; too much nitrogen gives leaves instead of flowers. A potash-rich flower fertilizer once buds form helps.
Cutting flowers
Cut stems when the lowest flowers on the stem have just opened, in the cool of the morning, and put them straight into water. Cut every few days. Flowering slows sharply if seed pods are allowed to form, so remove any pods and faded flowers. Cut sweet peas last about five to seven days in a vase.
Growing in pots
Dwarf and bush sweet peas grow well in pots at least 12 inches wide, and climbers can trail from large containers or climb a small obelisk. Keep them watered and in a sunny spot.
Companion planting
Sweet peas are often grown at the edge of the vegetable garden, where they bring in bees, but keep them clearly apart from edible peas.
Good companions
- Lettuce A cool-season crop that can grow at the foot of the trellis.
- Bush Beans Beans can follow in the same bed once sweet peas finish in early summer.
Keep apart
Avoid planting these close to sweet pea.
- Peas Sweet peas are poisonous and look similar, so never grow them where they could be mistaken for edible peas.
Pests and diseases
Aphids, slugs and powdery mildew are the usual problems, especially as weather warms.
Pests to watch for
- Aphids Clusters on shoot tips and flower buds; they also spread viruses.
- Slugs and snails Seedlings chewed off and holes in leaves in damp weather.
Diseases to watch for
- Powdery mildew White powder on leaves, worse as the weather warms; often signals the end of the season.
- Root rot Yellowing, wilting plants in cold, wet soil; plant in well-drained ground.
Common questions
Are sweet peas edible?
No. Sweet peas are poisonous, including the seeds and pods. Grow them only for flowers and keep them away from children, pets and edible peas.
When should I plant sweet peas?
In fall or winter where winters are mild, such as Florida, the Gulf Coast, Texas and California, and as early as possible in spring elsewhere. Fall-sown plants flower about three weeks earlier than spring-sown ones. Choose your region at the top of the page for the months.
Should I soak or nick sweet pea seeds?
Nicking the hard seed coat gently with a nail clipper or file is the safer method. Some growers soak seed instead, but long soaking can rot it. Do not nick pale, white or wrinkled seeds.
Why have my sweet peas stopped flowering?
Usually heat, dry soil, or seed pods forming. Keep the roots cool and moist with mulch, cut flowers often and remove pods. Once summer heat arrives, flowering ends.
How do I get longer stems on sweet peas?
Grow them in rich soil, pinch the seedlings early for strong side shoots, keep them watered, and cut the flowers regularly.
Sources we checked: NC State Extension Plant Toolbox: Lathyrus odoratus; New York Botanical Garden: Growing sweet peas; Royal Horticultural Society: Sweet peas growing guide.
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