Place the mixture in a quart jar and press to remove any air bubbles.
In the same bowl, combine the honey, vinegar, Whey, mustard seeds, and turmeric and pour the liquid into the jar.
Place a weight (such as a smaller glass jar) inside the jar to ensure the relish is fully submerged under the liquid.
Cover the top of the jar with cheesecloth, and secure with a rubber band or string.
Ferment at room temperature (roughly 70°F, or 21°C) for 3 days.
Cover with an airtight lid and store in the refrigerator overnight for the flavors to combine. The relish will keep in the refrigerator for up to 6 months.