Sweet Pea
Lathyrus odoratus
Fragrant climbing annual producing delicate ruffled blooms. Pick flowers frequently to encourage continuous blooming all summer.
Overview
Companion Planting
Good Companions
Runner Bean
CornBad Companions
None
Toxicity
Seeds and seedpods contain lathyrogens (beta-aminopropionitrile). Ingestion can cause vomiting, diarrhea, lethargy, tremors, and seizures in pets. In humans, consuming large quantities of seeds over time can cause lathyrism (skeletal and neurological symptoms). All parts are mildly toxic; seeds pose the greatest risk.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Pinch out growing tips when plants reach 10–15 cm to encourage bushier growth. Deadhead spent flowers regularly to prolong blooming. Provide support with netting, twine, or a trellis.
Common Pests
Aphids
Symptoms: Clusters of small green or black insects on shoot tips and flower buds. Leaves curl, become sticky with honeydew, and sooty mold may develop.
Treatment: Spray with insecticidal soap or neem oil. Blast off with a strong jet of water. For severe infestations, use pyrethrin-based insecticide.
Prevention: Encourage natural predators such as ladybugs and lacewings. Avoid excessive nitrogen fertilization. Inspect plants regularly in spring.
Slugs and Snails
Symptoms: Irregular holes in leaves and stems, especially on young seedlings. Slime trails visible on and around plants.
Treatment: Hand-pick in the evening. Apply iron phosphate-based slug pellets around plants. Use beer traps.
Prevention: Remove debris and hiding spots near plants. Use copper tape barriers around pots. Water in the morning so soil surface dries by evening.
Pea Moth (Cydia nigricana)
Symptoms: Small caterpillars found inside seedpods, feeding on developing seeds. Exit holes visible in pods.
Treatment: Remove and destroy affected pods. No effective chemical treatment once larvae are inside pods.
Prevention: Use fine mesh netting over plants during flowering (June–August). Sow early or late to avoid peak moth activity in midsummer.
Common Diseases
Powdery Mildew
Symptoms: White, powdery fungal coating on leaves, stems, and buds. Affected leaves yellow, curl, and may drop prematurely. Reduced flowering.
Treatment: Remove and destroy affected foliage. Spray with a sulfur-based or potassium bicarbonate fungicide. Neem oil can help in mild cases.
Prevention: Ensure good air circulation by spacing plants adequately. Water at the base, not overhead. Avoid planting in overly shaded or humid spots.
Fusarium Wilt (Root Rot)
Symptoms: Yellowing and wilting of lower leaves, progressing upward. Stems may show brown discoloration internally. Plants collapse and die.
Treatment: No chemical cure. Remove and destroy infected plants immediately. Do not compost affected material.
Prevention: Practice crop rotation — do not plant sweet peas in the same spot for at least 5 years. Use well-drained soil. Choose wilt-resistant varieties where available.
Sweet Pea Mosaic Virus
Symptoms: Mottled yellow-green patterns on leaves. Stunted growth, distorted flowers, and reduced vigor. Leaves may curl or become brittle.
Treatment: No cure. Remove and destroy infected plants promptly to prevent spread.
Prevention: Control aphid populations, which are the primary vector. Use certified virus-free seed. Disinfect tools between plants.