Endive and its curly-leaved form frisée are cool-season leafy greens grown as annuals. They produce a rosette of slightly bitter leaves used in salads. Bitterness drops in cool weather and rises in heat, so timing the crop for spring and fall gives the best flavor.
Endive bolts and turns bitter in summer heat, so it performs best as a spring or fall crop. To reduce bitterness further, blanch the heads about two to three weeks before harvest by tying the outer leaves up over the center or covering with a plate to block light, which pales and sweetens the inner leaves.
Lettuce Drop (Sclerotinia)
Lower leaves wilt and collapse onto the soil; a white, cottony mold forms at the crown and base, often with small black resting bodies. Plants rot at the base and die.
Remove and destroy infected plants and surrounding soil debris. Avoid overwatering and improve drainage and airflow. Rotate away from lettuce and other susceptible crops for 2–3 years. Do not compost infected material.
Downy mildew
Yellowing on top of leaves with grey-purple fuzz underneath. Spreads rapidly in humid conditions.
Remove affected leaves. Improve air circulation. Avoid overhead watering. Copper spray as preventive.
Aphids
Clusters of small soft insects on new growth and flower buds.
Knock off with a strong jet of water. Ladybirds and lacewings are natural predators. Insecticidal soap as last resort.
Damping Off
Seedlings collapse at the soil line with thin, water-soaked stems; seeds may fail to emerge or rot before sprouting.
Sow in well-draining mix, avoid overwatering, and ensure good airflow. Remove affected seedlings and let the surface dry between waterings.
Slug and Snail Damage
Large irregular holes chewed in leaves, with slime trails on foliage and soil.
Hand-pick at night, set beer traps, or apply iron phosphate bait. Remove debris and mulch where they hide.
Bacterial Soft Rot
Rhizomes turn mushy and foul-smelling; foliage yellows and pulls away easily at the base. Often follows borer damage or overly wet soil.
Cut away all soft tissue back to firm rhizome, let it dry, and dust the cut with sulfur. Improve drainage and avoid burying rhizomes. Destroy badly infected plants.