When to Plant Sweet Peas by Zone
Sow sweet peas in fall only in zone 7 and warmer. In zones 1 to 6, sow in late winter or early spring as soon as the soil can be worked. Dates by zone.
Published by ThriveThyme
sweet pea flowers sowing by zone
Some outbound seed-house links may be affiliate links.
The Short Answer
Sweet peas grow in cool weather and stop blooming in summer heat.
- Zones 8 to 10: sow in fall for the strongest spring bloom.
- Zone 7: fall sowing works in milder spots. In colder parts of the zone, late winter is the safer choice.
- Zones 1 to 6: do not sow in fall. Sow outdoors in early spring as soon as the soil can be worked, or start seed indoors in late winter and transplant.
Sweet Pea Planting Dates by Zone
These are ThriveThyme catalog windows. In zones 7 and 8, the fall window closes at the zone's average first frost.
- Zone 1: spring May 1 to June 15
- Zone 2: spring April 20 to June 10
- Zone 3: spring April 10 to May 30
- Zone 4: spring April 1 to May 20
- Zone 5: spring March 20 to May 15
- Zone 6: spring March 10 to May 10
- Zone 7: fall September 10 to November 1, or spring March 1 to May 1
- Zone 8: fall September 20 to November 15, or spring February 15 to April 20
- Zone 9: fall October 1 to December 1, or spring February 1 to April 10
- Zone 10: fall October 15 to December 15, or spring January 15 to March 30
Sow early in the spring window. Do not wait for your last frost date. Seedlings handle light frost, and late sowings run into heat before they bloom. Check your dates on the first frost date page.
Why Not Fall in Cold Zones
Sweet pea seedlings take light frost but not a long, hard winter. In cold-winter areas, extension guidance is to start seed indoors in late winter and plant out in spring. Fall sowing only pays off where winters are mild enough for young plants to hold through to spring.
How to Plant Sweet Peas
- Nick the seed coat with nail clippers so water can get in. Seed sprouts faster.
- Sow 1 inch deep and 2 to 3 inches apart. Thin to 6 to 8 inches apart.
- Put up a trellis or netting at sowing time. Tall types reach 6 to 8 feet.
- Protect seedlings from birds and slugs until they are 4 to 5 inches tall.
- Pick flowers often. Pods that form end the bloom.
- Sweet peas are toxic. Do not eat any part of the plant.
Next Steps
See the sweet pea page for spacing and care. Plan other flowers with flower seeds to sow in fall by zone and when to sow poppy seeds by zone.