Dill is one of the most useful herbs in the kitchen garden — the feathery leaves (dill weed) and the flat-topped seed heads are used in pickles, fish, potato salads, and Scandinavian cooking. Direct sow in early spring and every 3 weeks through midsummer for continuous supply. Dill bolts quickly in heat; succession sowing is the only way to have it all season.
Do not plant dill near fennel — they cross-pollinate and both lose character. The flat yellow flower heads are attractive to beneficial insects, especially parasitic wasps and swallowtail butterfly larvae. Allow some plants to go to seed for volunteers the following year.
Powdery mildew
White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
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.
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.
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.
Cercospora Leaf Spot
Small round spots with tan or gray centers and reddish-purple borders on leaves. Spots merge in severe cases, causing leaves to brown and die back.
Remove infected leaves and avoid overhead watering. Space plants for airflow and rotate crops. Apply a copper-based fungicide if the infection spreads.