agree except for cucumbers and summer squash which are used in the immature state. They don't get any sweeter, just not normally used as ripe fruit.

I think at least winter squash get sweeter if left for a while after picking. It's called "curing". The carbohydrates turn into sugars, and as the water evaporates, the sugars concentrate. Also the shell hardens, and the squash will last longer.

True winter squash if picked when fully developed (ripe) lose some of their water content when stored for several weeks (cured). Sweet potatoes also lose water when cured which concentrates the sugars.

When I was a kid, my neighbor grew watermelons. What he would do was to harvest the watermelon with part of the stem still attached. Then he would sit the watermelon on a table and put the stem in a bowl of sugar and water. He would leave it like that for a few days. He said it made the watermelon sweeter. ?????????????????????

Interesting! I also found a list of what ripens when picked and what does not. Very interesting.

The word "ripen" is an odd one. It doesn't necessarily mean that the flavor improves. In the case of tomatoes, "ripening" just means changing color. In the case of melons, it just means getting softer. I suspect that's also true with a lot of the fruit. The original question was about getting sweeter after being picked. That's not necessarily what "ripen" means. Certainly not the case for cantaloupe.

that is what I thought. I didn't think anything could get sweeter. I'm also confused how some vegetables and fruit immediately start to convert sugar to starch when picked but according to others above some do the reverse?

getting softer and changing color is good but not nearly as good as getting sweeter. Does anything actually get sweeter?

As we said, winter squash gets sweeter, but not necessarily because it is producing more sugar.

I don't grow bananas, but the ones I buy taste terrible to me when green and taste very sweet when they "ripen" to yellow and have a few brown spots. If there is sweetness there when they are green it is masked by some other flavors that make me spit out the fruit. But I think the sweetness develops as they change to yellow

That's correct. Ripening bananas are changing starch to sugar. In fact, that change is complete when the bananas are black and what we would call rotten. So if you want the sweetest banana, go for the mush.

I know watermelon won't ripen any more once off the vine, but my question is what is the best way to store them until time to eat and how long can they be stored uncut? I had to harvest (5) of them yesterday and want to be able to enjoy every last bit of each and every one, we've been waiting along time for these this year with weather-related set-back back in May/June.

They should last a few weeks or even a month in the fridge.

We went down to the lake this weekend and discovered that there was still a whole uncut watermelon in the fridge. It was picked the Friday before Labor Day. It still looked fine. A couple of the kids took it down to the lake to see if it would float which it did. After fishing it back out they then rolled it down a big hill and about half way down it broke open. They tasted a little bite and said it was still really good even after 4 weeks.

I hardly ever agree that anything is impossible. My personal opinion is that normally watermelon won't get sweeter after harvesting, but that there might be some uncommon or rare exceptions. However, I don't know of any offhand. There might be watermelons with different compositions than regular watermelons, and they might be more likely to exhibit this behavior.

If you pick some of the vine with your melon, it might be more likely to sweeten a little further, but that's just a guess. Maybe sun is needed, rather than just vine nutrients.

Now, I know Citron watermelons can be picked unripe, and they'll ripen in storage (they'll turn yellow—not as yellow as Royal Golden does when ripe, though) over a period of several months. However, they're not sweet whether vine-ripened or otherwise.

I've had a Kirkman melon (a kind of C. melo) that seemed to sweeten in storage. It wasn't ripe when I picked it, but once it got softer, I tasted it, and it was very sweet. Kirkman is supposed to be a winter type (like Valencia Winter melon is, but the fruit's a lot larger than Valencia Winter's; mine didn't keep a long time, though, but maybe longer than average; Valencia Winter keeps a long time, but it's so small).

It's also my opinion that Santo Domingo Winter watermelons get (and/or taste) sweeter when refrigerated for a few days, but that's perhaps not really the same thing.

If you just want a really good storage melon that'll ripen in the garden and store for a long time afterward, try Honeydew Orangeflesh. It's lasted longer for me than any winter muskmelon I've grown. Don't assume that all breeds of orange-fleshed honeydews are like this. They aren't. Huerfano Bliss, for instance, doesn't last very long by comparison.

I guess I'm waxing off-topic. I should be talking about watermelons. Try winter watermelons (they can keep in storage for a few months, but not nearly as long as Red-seeded Citron, which can keep probably over a year): e.g. Navajo Winter, Navajo Red, Santo Domingo Winter, Santo Domingo Dark Green, Santo Domingo Brown Seeded, Winter Queen, King Winter, King and Queen Winter, Wintermelon, Black-seeded Ice Cream, and maybe others. Winter watermelons aren't the same as shipping melons (winter watermelons are not necessarily extra-durable; they just keep longer). They tend to have a tougher skin (I don't mean a tougher rind, but the actual skin is tougher; I eat rinds—so that's how I know). The rind need not be thick at all (although some breeds have thick rinds). The Santo Domingo ones are my favorites (two of those three have thick rinds), but I think I've had the best storage with Navajo Winter (not that I've tested them all, as I'm often anxious to eat them). I've grown all the ones I've listed, except for Black-seeded Ice Cream and King and Queen Winter. Santo Domingo Winter is the earliest to ripen of those I've tried. Yes, they ripen fully on the vine the same as other watermelons, and they're not later, necessarily, either. They just store for a long time after harvesting (up to four months or so).

"I know watermelon won't ripen any more once off the vine, but my
question is what is the best way to store them until time to eat and how
long can they be stored uncut?"

Store them in a cool place with good ventilation. Here, that might be in an unheated garage, or a cool basement... but a refrigerator is best, if you have room for it. The storage time may vary, depending upon the variety, and the storage temperature. I keep mine in the basement, and they last for a couple months. Quality will deteriorate, mine begin getting spongy or hollow from the inside out... but even then, the flesh closest to the rind remains pleasant.

Wow, they keep at least a month in the fridge? That is good, I have one "Sugar Baby" left in the fridge that I harvested last week, and I think there may be one more out in the garden that may be salvageable -- it was the right size, but wanted to leave it as long as I could in an attempt to sweeten it up. The others are much too small to be ripe. Still, happy what I did harvest -- I'm happy to have gotten anything this year out of any of the melons (the "Alvaro" Charantais were especially good, as were the "Crimson Queen" watermelon).