Has it been overly warm/hot? Overly wet? Good air circulation in the net house to keep the heat down? Consistent soil moisture levels, no excess nutrients, etc? Often a result of some sort of plant stress but I can only guess as to the particular cause.

Dave

The overall conditions last year were reasonable, may be a little drier then usual, but I was watering. What puzzled me is that LL was producing as usual, just as usual late. And those just produced female flowers - a lot of them, and then dropped at first all of them, later - may be 2/3... But the plants themselves looked normal, not stressed at all, until PM came... This year I planted 2 different European cukes , not same as last year, and they already flower - females) But do not see any real growing in fruit. Though weather is not cooperating this year - first very dry and hot, then 5 inches of rain in 3 cold days and now 3 cold nights in a row...

I have the same situation with Diva. I grow them in containers, indoors, with consistent moisture, constant sunlight all day, and adequate nutrients.

I have grown it before in identical conditions, and the previous time, everything set great. This time, I've lost dozens of fruits, none have set, and the plant is now full size, and capable of supporting many large growing cucumbers, but they're not setting. I'm at a loss and am about ready to start a new variety. I almost wish Diva wasn't gynoecious so I could have some male flowers to pollinate the females with.

What I found so far, is that gynoecious European cucumbers, especially the ones that flower in bunches(many fruit in the same place) are "very demanding for nutrients". Got it from some European forum. Unfortunately, no specifics. So this year I started to feed them every week with general fast release tomato food with addition of some blood meal. So far so good -

We got first 9 cucumbers picked(from 6 plants). I still see few dead ones, but the weather was so crazy this spring, that I am surprised the plants survived at all. I also feed "Little Leaf" as well and it gave me interesting results. Usually, they grow one branch up the trellises with only male flowers... And only later start to spread. This year they look like green crabs - 6-8 short legs all directions. And on those side branches I already see female buds, they are too young to flower yet, but still, it is much earlier then usual.

After more research, I found this overwhelming amount of data that indicates the different requirements between initial growth, and formation of fruit - true it is primarily for hydroponics, but it clearly indicates potassium is crucial for fruit formation. It's likely I haven't adequately amended for potassium, so as a stop-gap measure, I added some liquid macro & micro to its water supply so some potassium and other goodies are immediately available, so we'll see what happens.

The stop-gap measure worked, I now have several fruits growing.

I heard you cannot plant Parthenocarpic cucumbers with other types. Parthenocarpic cucumbers were made to self pollinate. if they’re put with others that need pollination it keeps them from producing. Genetic issue.

Parthenocarpic cucumbers are not self pollinating - they set sterile fruit without being pollinated. Those cucumbers will be seedless. That makes parthenocarpic cucumbers well suited for growing in greenhouses or under cover, since they will form cukes without bees.

If allowed to be insect pollinated by ordinary cucumbers however, they still produce cucumbers; but those cucumbers will develop seeds.

I know this is an old thread, but I'm having same issue. I planted Muncher parthenocarpic cuke seeds at start of January in my heated, lighted greenhouse. They have taken off and started flowering over a week ago. Lots of flowers, both male and female. But NO fruit set. Plant looks very healthy, and I have fed them with Maxsea flowering formula. I have even tried pollinating using paintbrush, but nothing. Tons of female flowers/ovaries but none grow. In another area of my greenhouse I have several Picklebush cukes growing. They are not parthenocarpic, so I hand pollinate, and they are doing just fine and have been setting fruit.

Anyone have ideas on how to get the Munchers to set?

Thanks! I'm reading more threads on this and it does seem to be a matter of time. Fingers crossed!

I'm having the same thing with my little leaf cuc's. Plant is doing amazing and making tonsssss of blooms but no fruit yet. However, we have been having some serious temperature swings of 75-90 lately. I'm hoping that once our weather calms down, things will improve. I've also started giving Alaska Fish Fertilizer once a week instead of everything 3 weeks and a humic/fulvic acid additive once a month. Fingers crossed! Will be interested to see how your plants come along Tastie and mroyboy :)

I started some Munchers this spring in my garden, and they've been doing well. Unlike the ones in my greenhouse, these ones have had no problem setting fruit. I think morning temps in the greenhouse were frying the plants. I live in a cool climate, and our summer has been cooler than usual. I don't think we've had any temps above high 70s. Nights have ranged from low to high 50s. I also have 3 other varieties of cukes growing, and have not found that to interfere with the production of the parthenocarpic variety.

at @Andrea Tyree - don't overdo nitrogen, as it could promote lots of green growth at the expense of flowers and fruit. You might want to try a food specifically for promoting flowering and fruiting. https://organicgrowersschool.org/gardeners/library/basic-plant-nutrition/

Yea....maybe I will try that :) Thanks!

very helpful thread!

Thanks to all who commented. I thought I was the only one with beit alpha parthenocarpic cucumbers not maturing. The fruits just sit there with the dried flowers, then turn yellow. Fish emulsion, worm castings, and compost made the vines taller but cucumbers remained puny, about 1".

I removed beit alpha and replacing it with Spacemaster. I will never sow belt alpha again.

This is time growing Alpha Beit cucumbers. The first female flower opened two days ago. Fingers crossed