To the extent that cucumis sativus (as in, plain 'ol cucumbers) can't take your heat, try Armenian cukes. I've been growing them for years and every hot hot summer I have them coming out of my ears. They taste exactly like regular cucumbers, are burpless, and when you slice into them, look pretty much the same as well, but can be long and unusually shaped fruit. Now, these guys are actually cucumis melo, so botanically they are actually melons. Go figure. We're currently using them by the bazillions in salads, pickling them, and even making cold cucumber soup with them, even as the temps are in the high 90sF.

peggyhamill, I have zucchini with only female blossoms that are producing fruit. There's no one else in the neighborhood growing zucchini (I live in an area of condos), so it's highly unlikely they have been pollinated. The fruit grow very slowly, and most stop growing at around 5" long. But currently, I have one growing to full size for which the flower never even matured or opened. I grew the plants from a Tasty Black Patio start produced by Westwind Gardens. Before this happened, the production had slowed, possibly due to hot weather, and I gave them some fertilizer and Morbloom (0-10-10). It's happening with both zucchini plants that came from the same tray of starts.

I have never had this happen. The male flowers have been blooming for weeks but still no female flowers or fruit. Bees are all over the blossoms so I’m leaving the plants for them. Has this happened to anyone else?

That's an interesting strategy about vine cutting, Dave. I'll see if that works. There is a lot in the literature about the distribution of male and female flowers on nodes and node triggers. Here is what I‘ve learned about sexual expression in cucurbits from the research papers online. Female flower production is reduced in high temps, especially high nighttime temps. There is a clear photoperiod effect as well, in that longer daylength (more light) reduces female flower production. So one strategy for female flower production is some shadecloth, perhaps. It is stated, however, that this photoperiod doesn’t appear to play a major role in field production. With regard to fertilization, high nitrogen tends to reduce female flower production, but low nitrogen reduces ALL flower production. So nitrogen starvation isn’t necessarily a good strategy to get more female flowers. Quite a bit of evidence that extra potassium can increase production of female flowers. So that’s a potentially useful strategy. There are LOTS of chemical additives that can change sexual expression. An interesting one is ethylene gas. You can add stuff to soil that produces ethylene. Ethylene is a powerful growth hormone, and it is well understood that ethylene promotes fruit ripening. But ethylene also strongly promotes female flowers! Now, what is kind of fascinating is that plants themselves produce ethylene (leaves, stems, roots, etc. ) So poorly ventilated plants have more ethylene around them, and more female flowers. That would suggest that female flowers will be more prevalent in greenhouses, and in dense stands of foliage that block the breeze. The temperature effect is a bit of a PIA for me. I delay plantout of squash until mid-summer, to avoid SVBs. That means that temps are very high when I want the plants to set fruit. Ideally, you’d want to set fruit when it is cooler, before the summer heat sets in, because there would be more female flowers, and then use the summer heat for developing and ripening the fruit. All that being said, a general rule is that as plants mature, male flowers come out first. That’s a low-energy way to attract pollinators. Takes more plant energy to produce female flowers, so the plant really only wants to do it when pollinators are around. But since cool temps enhance female flower production, that rule can be broken. So OK, "wait and see" is still good advice, and "luck of the draw" pertains as well.