Identify what you’re seasoning (soups, casseroles, chicken salad, pickling, or stuffing) so you choose a substitute that behaves similarly as it cooks.
Start with the listed ratio and add early for sauces/soups or mix in after for cold dishes.
Taste after the first simmer/softening step (or after mixing for cold dishes) and adjust in small pinches.
If the substitute is salt-forward (like celery salt), correct overall salt in the recipe rather than adding more celery flavor.
Let the dish sit 5 minutes before the final taste—celery-like flavors bloom as they hydrate.