You will need to bag individual female blossoms and hand pollinate from that same variety.

"I've seen other people grow multiple varieties."

Yeah that is no problem if they don't save the seeds. If you want to save the seeds then you will have to bag some blooms and hand pollinate.

"Bug netting" can mean many different things, many of which would not work. It has to be a very, very fine mesh bag. I have seen people here recommend the small wedding favor bags they sell at Walmart made from organza.

Organza-Bags

Then once they begin to grow mark those fruit and save seed only from them.

Dave

Thanks. Do you know of a video that shows how to bag the blossoms correctly? There's isn't one video on Youtube that shows this. Weird huh? - Dave

Well, you have to first bag a female flower before it opens. Basically... anything that covers it so bugs can't reach it once it opens. I've found with some crops, you have to be very gentle when you tie the bag at the bottom. Then, when the flower opens, from the 'best' vine of the same variety (it can be that same vine...) find a male flower that is open, take the bag off the female, transfer the pollen from the male to the female - for this step many sources will tell you to use a small paint brush or a cotton swab, but honestly... it's easiest for some plants to take the male flower itself and gently use it to transfer the pollen to the female. Then, you immediately re-bag the female. When the female flower begins to desiccate, and the ovary (just below the flower) begins to swell, you can remove the bag.

A video? No don't know of one. But it is pretty much self-explanatory. Loosely tie the bag at the base of the bloom and be sure to include the tiny swelling at the base of the female bloom. rgreen detailed it well.

Dave

If you look up how to hand pollinate squash for seed saving you can find all kinds of information and videos. What works for squash works good for melons too except the melon flowers will be much smaller.

https://www.youtube.com/watch?v=WviRwfnvkec

In the above video they used tape instead of a bag but they both accomplish the same thing.

Rodney

I always bag the male flower, also, because an insect can transfer pollen from another variety into a male flower, too.

here's a you tube video...there are tons of them, but look under "hand pollinating" of squash, melon, etc...the technique is the same...

https://www.youtube.com/watch?v=6ay4smh2FfQ

this guy uses string instead of bags

https://www.youtube.com/watch?v=f1-U15kj1tg

"I was given a bunch of watermelon seed this year (4 varieties) I want to grow them all and save the seeds."

My first question would be if you know the varieties you were given? If they were hybrid types of melons then saving the seeds won't work. Saving heirloom seeds works, such as the Moon & Stars variety is ok.