Golden Self Blanching

Celery is especially prone to leaf blight and fungal leaf spot during cool, wet weather; remove yellowing leaves and improve airflow by spacing plants and watering at the soil line. For pest pressure, watch for aphids clustering on tender growth—spray them off with a strong stream of water and, if needed, use insecticidal soap targeted to the undersides of leaves. If blight starts spreading, discontinue overhead watering and prune affected foliage to slow further infection.

Harvest at about 75 days from sowing (or when the stalks are thick, crisp, and reach usable height), typically when the bases feel firm and leaves form a dense crown. You can begin “cut-and-come-again” on outer stalks for a few weeks, but for best quality wait until most stalks are full size before doing a full cut. If stalks are stringy or the stems are thin, give the plant a little more time before harvest.