Normally, the size of watermelon is decided by the variety. For example, a Sugar Baby will not get very big.

How many per vine ? there in not a set standard. It depends on the plants vigor, growing conditions, length of growing season, so forth. But I would look at it this way:
HOW LONG WILL IT TAKE FROM FLOWER TO A RIPE WATERMELON? Lets say that it will take 7 weeks. So any flower has less than 7 weeks chance will not ripen. I would, therefore cut/ discourage any new growth/flower within that last 7 week window of time. MAYBE, if the vine has too many fruits, I'll start that process sooner.

So, not knowing specifics about the variety in question and the length of your growing season I cannot be more specific.
I am sure other member can give you better answers.

Well, I mentioned that I was growing OrangeGlo which I've read bears fruit anywhere from 10-30lbs. I'm in zone 7b in Oregon and my growing season is from mid May to late September/mid October and these were transplanted June 1. I was just wondering if I should limit its production to a specific amount of fruit per vine and/or plant so as to keep the quality of it I guess. Though, your example was helpful!

Orangeglo is a ninety day melon. Takes a long time to ripen and and does not size down well. A 20-30 lb melon will be be delicious, a 10 lb melon melon barely edible. In your climate I would not leave more than three melons per vine.
{{gwi:40834}} It is also a melon with a very tender rind and will not tolerate much handling.
{{gwi:14270}}

Wow! Those watermelons look amazing!
Okay, so no more than 10-12/plant. Thanks =D!
So would thumping orangeglo not be recommended because of the rind?
My watermelons have been loving the weather, 90-100+ here and sun all day.

Also, do you stress the watermelons be not watering before picking? If so, when should I stop watering them? 2 weeks before picking or so?

Orangeglo is one of the most vigorous of watermelon plants. Last year I had one Orangeglo. It set one 35 pounder on the first set. One the second litter I left 3 fruits and they weighed 99 pounds. 3 is the upper limit for a very healthy plant. Otherwise size declines.

Two years ago i had the most healthy plant imaginable and I harvested 11 melons that totaled 234 pounds...don't try to do that.

Orangeglo can be very tasty, but often it is a bit grainy and softish.

I don't irrigate, so watering is by rain alone.This climate and soil are excellent for watermelons so most of my work is preperation, after planting I cultivate until th vines start to run. next step is harvest. Thumping is ok, but handle Orangeglo very carefully. A three inch drop can result in multiple pieces.

Someone sent me yellow fleshed watermelon seeds in a trade. How badly I wish people wouldn't do this! Are there many yellow fleshed watemelons?

Animepiper,

While I hope for the best for you, don't set your sights too high. I farmed for 10 years near you in the Applegate valley and had a very hard time growing those large watermelons. Crimson sweet did ok for me but if I got 3-4 melons per plant I'd consider that a success. I had much better luck with the smaller icebox watermelons like starlight and yellow doll.
It was the early frosts in late sept. that usually did the melons in. If this year is like last, with heat into Oct., you might have a chance.

Keep us updated.

-Mark

There are many varieties of yellow fleshed melons, Orangeglo,
IMO is one of the best. You can thump it to see, if it is ripe, but a better way to check for ripeness, is the underside, will develop orange streaks. But orangeglo is a fairly long season melon and needs lots of heat in order to truly develop. It's too bad that more people don't try these melons, because they are much sweeter than red fleshed melons. But since you won't find them in grocery stores. the general public doesn't even know they exist.

rayrose, maybe for you they are much sweeter, but the broad statement that orange is sweeter than red is just not true.
U. Of W did a great study of over 100 watermelons types and many of the red fleshed melons score a much higher brix level than Orangeglo.

Here is a link that might be useful: Watermelon study

This is the other one (1 of 2) that has gone kind of soft. They all set at the same time so I'm thinking these probably won't get much bigger.

I thought you were growing Orangeglo. That's not it.

Surprise. Ray is correct. May not even be orange fleshed. Tendersweet maybe, but there are dozens of red flesh melons out there with that shape and markings. In any event, remove misshapen bottle nose melons, they will never develop properly.

Hmmm. Then I guess it must've been labeled incorrectly cause that's what it said when I bought them. Oh well, I guess if that big one matures I'll see what it is.

Any idea why the others would be getting soft on the end?

Incomplete pollination