Don't buy bitter melon seeds
At my first attempt to germinate bitter melon from seeds I bought a packet of it from a local grocer and another from a "reputalbe" dealer fron Canada. So far only out about $10. However my success was zero.
Then a simple thought came to me. Out of my weekly supply of fresh bitter melon I decide to make use of the seeds that I normally get rid of. I removed some very carefully so as not to nick or damage them. I cleaned and washed the seeds and without any further step I put them in the proper potting mix prepared in a shallow wooden box. Two weeks later I am now counting eight little beauties , from half to two inches tall . The secret is to keep them warm and give them warm water from a spray bottle as needed, depending where you live.
Let me have some good responses from your attempts.