Put celery seed in grinder. See notes above about grinder options.
Grind celery seed to desired consistency.
Mix with salt.
Store in a closed jar in a cool, dark place.
For another version of this recipe that happens to be also work for the AIP diet, use celery leaves instead of celery seed. The proportions are up to you, but one option is about 1 tablespoon of sea salt to 6 tablespoons of celery powder.