Curled

Chervil often suffers from powdery mildew and leaf blights in warm, humid conditions; keep plants evenly spaced for airflow and water at the soil line rather than over the leaves. If you see white powdery growth or expanding brown leaf spots, remove badly affected leaves and improve ventilation; avoid heavy nitrogen feeding to slow lush, disease-prone growth. Watch for aphids on tender curled growth—spray a strong stream of water to knock them off, and repeat every few days until new shoots are free of them.

Harvest when plants are about 4–6 weeks old and have developed multiple true leaves (usually around 30–45 days from sowing), before they bolt in warm weather. Pick leaves in the morning by snipping outer growth; regular harvesting encourages more tender leaf production. If flower buds form or the plant starts stretching rapidly, harvest immediately and plan to sow again, because leaf quality drops as Anthriscus cerefolium turns to flowering.