Sanitize everything that will be used in the brewing process.
Put 1/2 gallon of non-chlorinated water and the dandelion petals in a pot and bring to a boil. Turn off the heat and let steep for 15-20 minutes.
Add the honey and stir to dissolve, then add the juice of the lemon and carefully pour the honey water mixture into the jug using a funnel.
Top off the jug with cold non-chlorinated water, leaving at least 2 inches of head space on top. Put the lid on the jug and gently mix everything around a bit.
Make sure that the temperature of the must is below 90°F, then add 1/2 packet of champagne yeast. Put the lid back on tightly and this time shake the jug for a minute or two to distribute the yeast.
Put a little water in the airlock to the line, then put the rubber stopper end into the jug. Put the jug in a dark place. It should start bubbling within 12-24 hours.
After about 6 weeks of fermenting, or once the bubbling has completely stopped, the mead can be bottled and aged. When bottling, it is helpful to put a piece of cheesecloth over the end of the auto siphon that goes in the jug to keep the dandelion petals out.
If you put a small piece of cheesecloth attached with a rubber band over the end of the siphon that goes into the jug, it will keep the petals out.