stopped flowering

[dveg]

My melons and cukes were going great guns, producing vastly more than I could eat for many months. But now, although the foliage looks pretty healthy, productivity has stopped. That's because flowering stopped. No flowers. Zilch. Now, I have had a few weeks of 100F+ heat, but they were kept well watered. I figured that maybe only new foliage would flower, so I hit them hard with nitrogen. Lotsa green, but still no flowers. This happened last year as well. Now, my growing season lasts for a few more months. So, have these guys just reached the end of the line, and do I need to prematurely rip them out? Why? BTW, my soil tests show loads of P and K.

[applestar]

I think you are correct in assumption that flowers develop on new side/sucker shoots/vines and old vines won’t grow new flower buds. Does “lots of green” mean they grew new side shoots since nitrogen boost? Are you letting the side shoot nodes set down roots? No blossoms on those new side shoots?

You might be missing some micronutrients that affect NPK uptake and availability? In addition to Espoma Tomato-tone and Tree-tone, I remember adding extra dolomitic lime (calcium +minerals), Epsom salts (magnesium sulfate), and a sprinkling of borax (boron) when I prepped my melon bed this year.

Mine are blooming but not readily setting fruits. I’m not hand pollinating this year so that might be part of the problem, but I do see pollinators. I haven’t supplemented fertilizer but they should be getting compost pile leacheate. Even so, newer Watermelon are starting to show blossom end rot, and some of the melon vines in less well prepped bed are stunted.

[dveg]

Yes, no blossoms on new foliage. I'm skeptical about micronutrient unavailability. If micronutrients weren't available, I wouldn't have had a great growing season. Micronutrients don't just suddenly disappear. This same thing happened last year.

[applestar]

That’s really strange. With my pitiful melons and watermelons, as well as enthusiastically producing cucumbers, as the season progresses and they are slowly overcome by fungal diseases (usually powdery mildew) and I have to clip off diseases leaves until the vines are nearly bare, they will keep trying to grow side shoots with tiny leaves and clusters of floral trusses until the very end.

— Last gasp of each vine will be the very end cluster of leaf buds and floral buds on several stunted side shoots (often targeted by stinkbugs and cucumber beetles in their weakened state) that I end up “calling” since there isn’t much chance of supporting fruit growth even if they were to bloom and set fruits.


...oh... wait, are you seeing floral clusters and flower buds at all? Maybe something is eating them before they can bloom?

[dveg]

Nope. No floral cluster or buds. No diseases or pests. I'm thinking that the high heat just stresses the plants, and interferes with flowering. If that's the case, then just salting with N, and keeping them around until it cools off may help. Funny that everyone says that melons like heat. To most everyone, "heat" is 85-90F!

[dveg]

I should add that after salting the soil liberally with ammonium nitrate, the foliage is coming back. Many smaller green leaves are appearing. I have a theory. Two things happen when it gets very hot (1) heat stress and (2) frequent watering. I've been putting 1/2" of water on every two or three days during this fierce heat, and I'm guessing that nitrates, which are very soluble, were getting effectively leached out. Nitrogen deficiency would prevent new leaves from developing, and new flowers forming on that foliage. In previous years, when this happened in August (worst of the fierce heat), I just let the plants fade, and ripped them out. This year, I'm going to lather on the nitrogen, and see it the situation can be fixed.

[rainbowgardener]

Frequent watering makes sense. We now have a break in the weather, but we had a long stretch of temps in the mid to high 90's. With our humidity that meant sometimes heat indexes of 104 or even 106. And very little rain. I've been watering a lot, but not as much as you. My spring planted butternut squash is looking kind of pathetic, it wilts in the heat and now has powdery mildew, so starting to get more bare of leaves, but still putting out new flowers and fruits. I'm about to cut it off to stop that to let it ripen the ones that are there better. My squash plants that were planted in summer are thriving and flowering.

[dveg]

Well, that's another possibility, that plants just get "tired" after producing a lot. After last year, I considered that as a possibility, and this year specifically planted a few a month or two later. Those newer plants now look the same as the older ones, so that possibility doesn't seem to pertain.

[imafan26]

Although squashes like heat, the temperate ones don't like 100+ degrees. My vines usually stop producing new flowers until it gets cooler or the flowers are all male. Disease is the usual way the vines get done in. The ones that survive usually start to produce again once the temperatures abate.

Long beans and wing beans don't seem to stop even with the heat, but they are usually partially shaded by whatever tree they are climbing. They do fine as long as they get enough water.

[dveg]

Yes about squashes not liking 100+ temps. I just had some butternuts give up the ghost because of heat. They wilt every day, even soon after watering. Wilting is OK, as they usually pop back, though I believe some damage is being done. But I don't think anyone here was talking about squash in 100+ temps. I'm talking cukes and melons, and they can take the heat, at least growing foliage.