Wash the flower heads well in cool water. Gently open the flower heads and remove only the petals, discarding the green flower head and stem. Place the dandelion petals into a non-reactive container such as a gallon size mason jar or large glass crock.
Add 4 cups of boiling water to the petals, making sure they are completely covered. Allow the dandelion flower tea to cool to room temperature.
Once the flower petal tea has completely cool, place into the fridge and allow it to steep for an additional 24 hours.
Prepare jars, lids, and canner.
Using a fine mesh sieve, strain the flowers, gently squeeze the petals to release as much of dandelion tea as possible.
Place 3 cups of the strained tea into a large non-reactive pot. Add the lemon juice and pectin.
Bring mixture to a boil.
Add sugar and return to a boil making sure to stir continually to prevent scorching. Allow the mixture to hard boil for 2 minutes. Skim any foam which may be present.
Remove from the heat. Using a jar funnel and ladle, fill ½-pint canning jars leaving ¼ headspace.
Process time is based on your altitude, see the chart in the article.