Everything you need to know about Lathyrus Seeds
Lathyrus Seeds (Sweet Pea) Questions and Answers:
(Updated 02/03/2025)
When should I plant Lathyrus seeds?
Lathyrus seeds (sweet peas) are best sown in cool weather. For most regions, this means autumn for blooms the following spring, or early spring as soon as the soil is workable. Autumn planting allows roots to develop before winter. Soak seeds in water for 24 hours before sowing to improve germination rates.
Where should I plant Lathyrus?
Sweet peas need a sunny spot with at least six hours of direct sunlight daily. They prefer well-drained, fertile soil. Amend the soil with compost or well-rotted manure before planting. They also need support to climb, like a trellis, fence, or netting.
How deep and far apart should I plant Lathyrus seeds?
Plant Lathyrus seeds about 2.5 cm deep and 15-20 cm apart. If you're sowing in rows, space the rows about 30-45 cm apart. Firm the soil gently after planting and water thoroughly.
What kind of support do Lathyrus need?
Sweet peas are climbing plants and require support to grow vertically. Use a trellis, netting, or bamboo canes. The support should be sturdy enough to hold the weight of the mature plants and flowers. Tie young seedlings to the support as they begin to grow.
How often should I water Lathyrus?
Keep the soil consistently moist, especially during germination and early growth. Water deeply at the base of the plant, avoiding overhead watering which can encourage fungal diseases. Once established, sweet peas are relatively drought-tolerant, but regular watering will promote better flowering.
Do I need to fertilize Lathyrus?
Sweet peas benefit from regular feeding. Apply a balanced liquid fertilizer every two weeks during the growing season. Avoid high-nitrogen fertilizers, which can encourage excessive foliage growth at the expense of flowers.
How do I encourage more flowers on Lathyrus?
Regular deadheading is essential for continuous flowering. Remove spent flowers before they form seed pods. This prevents the plant from putting energy into seed production and encourages it to produce more blooms.
How do I pinch out Lathyrus seedlings?
Pinching out the tips of young seedlings when they are about 10-15 cm tall encourages branching and bushier growth. This results in more flowers and a stronger plant. Pinch out the main stem above a set of leaves.
What are some common problems with Lathyrus?
Sweet peas can be susceptible to powdery mildew, especially in humid conditions. Ensure good air circulation and avoid overhead watering. Slugs and snails can also be a problem, so take preventative measures.
Are Lathyrus annuals or perennials?
Lathyrus odoratus, the commonly grown sweet pea, is an annual. This means it completes its life cycle in one year. Other Lathyrus species may be perennial, but are less frequently cultivated for their flowers.
How do I prepare Lathyrus seeds for planting?
Lathyrus seeds have a hard outer shell, so soaking them in warm water for 12-24 hours before planting helps speed up germination. Another method is that you can scarify the seeds by gently nicking the surface with a nail file or sandpaper. This allows water to penetrate and encourages faster sprouting. Without pre-treatment, germination may take longer or be inconsistent.
Should I start Lathyrus seeds indoors or sow them directly?
Lathyrus seeds can be started indoors in biodegradable pots or sown directly into the garden. Direct sowing is often preferred because sweet peas have delicate roots that don’t like being disturbed. If starting indoors, plant them in deep containers (at least 7-10 cm) to accommodate root growth and transplant them carefully. Harden off seedlings before moving them outdoors to prevent transplant shock.
What type of soil is best for growing Lathyrus?
Lathyrus grows best in well-draining, fertile soil with a pH between 6.0 and 7.5. The soil should be rich in organic matter, so adding compost or well-rotted manure before planting is beneficial. Avoid overly acidic or heavy clay soil, as poor drainage can lead to root rot. Loosen the soil to a depth of at least 20 cm to encourage strong root development.
How much sunlight does Lathyrus need?
Lathyrus prefers full sun, requiring at least 6-8 hours of direct sunlight daily. In very hot climates, they may benefit from partial shade in the afternoon to prevent stress. Insufficient sunlight can lead to weak, leggy growth and fewer flowers. In cooler regions, a sunny location ensures the best flowering and healthy plants.
How often should I water Lathyrus?
Water Lathyrus regularly, especially during dry spells, but avoid waterlogging the soil. Keep the soil consistently moist but not soggy, as excessive moisture can cause root rot. Water deeply about once or twice a week, depending on rainfall and temperature. Mulching around the base helps retain moisture and keeps the roots cool.
How long does it take for Lathyrus to bloom?
Lathyrus typically takes 10-12 weeks from sowing to start flowering, depending on growing conditions. Regularly deadhead spent blooms to encourage continuous flowering. In cooler climates, they bloom throughout late spring and summer, but in hotter regions, flowering may decline in mid-summer. Providing good soil and adequate water helps prolong the blooming period.
How do I prevent pests and diseases in Lathyrus?
Lathyrus can be affected by aphids, powdery mildew, and fungal diseases. Check leaves regularly for pests and use insecticidal soap or neem oil if necessary. To prevent fungal issues, provide good air circulation by spacing plants 15-20 cm apart and avoid overhead watering. Crop rotation and removing plant debris at the end of the season can reduce disease risks.
Can I save seeds from Lathyrus flowers?
Yes, you can save Lathyrus seeds by allowing the pods to mature and dry on the plant. Once the pods turn brown and crisp, collect them and remove the seeds. Store the seeds in a cool, dry place in a paper envelope or airtight container. Keep in mind that hybrid varieties may not produce true-to-type plants from saved seeds.