Sweet peas (Lathyrus odoratus) are a cool-season favorite, prized for their complex perfume and delicate, ruffled blooms. This guide covers how to get them from seed to vase in your own backyard.
Sowing for Success
Sweet peas thrive in cool weather and despise heat. In USDA zones 7 and warmer, start seeds in late autumn or winter. In zones 6 and colder, sow seeds indoors 6 to 8 weeks before your last spring frost or directly into the garden as soon as the soil can be worked. Plant seeds 1 inch deep and 3 inches apart in well-drained, rich soil. Soaking your seeds in water for 12 hours before planting can help speed up germination.
Providing Support
These plants are vigorous climbers that require structural trellising to stay healthy and productive. Without a support system, they will sprawl on the ground, making the stems curly and prone to rot. Use a sturdy net, a hog wire panel, or a wooden A-frame at least 6 feet tall. As the vines grow, gently guide the tendrils toward the support structure to encourage upward growth.
Pinch the central stem of your sweet pea seedlings once they reach 6 inches tall to encourage lateral branching, which results in more stems and flowers throughout the season.
Mastering the Harvest
Consistent harvesting is the secret to a long blooming season. Sweet peas have a simple rule: if you let them set seed pods, the plant stops flowering. Pick stems when the bottom one or two flowers are just starting to open. Use sharp, clean snips to cut stems at the base of the plant. Since they are delicate, place them immediately into a clean vase filled with cool water to maximize their vase life, which typically lasts about 5 to 7 days.
Growing Tips
- Mulch around the base of the plants to keep the roots cool as temperatures rise.
- Water consistently, keeping the soil moist but never waterlogged.
- Feed with a balanced liquid fertilizer every two weeks once the plants begin to climb.
Growing sweet peas rewards you with a home filled with the scent of spring and endless stems for your favorite small bouquets.