Step 1: Harvest dandelion flowers from a clean, pesticide-free area and separate the yellow petals from the green bases until you have 2 cups of petals.
Step 2: Place petals in a heat-proof container and pour 4 cups of boiling water over them. Let cool, then refrigerate to steep for 12-24 hours.
Step 3: Strain the dandelion tea through cheesecloth or a fine-mesh strainer, pressing the petals to extract all the liquid.
Step 4: Measure 3.5 to 4 cups of the strained dandelion tea and pour into a large pot. Add the lemon juice and powdered pectin.
Step 5: Bring the mixture to a full rolling boil over high heat, stirring constantly.
Step 6: Add the sugar all at once and stir until dissolved. Return to a full rolling boil and boil hard for exactly 1 minute.
Step 7: Remove from heat, skim off any foam, and pour into sterilized jars, leaving 1/4 inch headspace. Process in a water bath canner for 10 minutes or store in the fridge.