I grow F1 cucumbers (female flowers only) but my other cucurbits pumpkins, watermelons etc often produce loads of male flowers and then females.

Not sure if you can buy them where you live but I would recomend iznik cucumbers for hydroponics, I have picked about 15 so far from the one plant, they are smaller than most but grow well in containers.

Just throwing out a couple things:

All male flowers in the first week or so of flowering is common on some varieties. However, once you get female flowers they have to be pollinated. How did you get the thrips under control? If you used an insecticide, you may have used one that also deters pollinators. The female flower doesn't stick around long if not pollinated. You can cut a male flower and touch the pollen from it to several females to hand pollinate. Or you can use a small paint brush or q-tip. Generally, you want the female flower to be open, but you can gently tear the flower open if you need to.

Do you possibly have too high of nitrogen content? That is a common reason for flowers dropping on other plants. Switch to a bloom solution if you haven't. I can't remember what nutes you are using or if you have mentioned it elsewhere. Can you refresh my memory?

When I first read the original post earlier today, I was going to ask if they were grown inside or outside. Then considering the bug problem I would assume they were most likely grown outside. Even so I was going to ask if they tried to hand pollinate them. But because the poster said the female flowers were falling off before they even began to open up, I figured that question would be kind of pointless.

Yeah, that's why I mentioned the gently tearing open part. Sometimes, the flower opens only for a very short period in the day, so it's easy to think it never opened if you didn't catch it. Not sure if ethno is aware, but they don't stay open once they open. They generally open and close every day and the weather can affect this. If it is overcast or rainy, I've noticed they are less likely to open. I actually just came in from pollinating mine. The female flowers aren't open on mine, either. It's been so rainy half the state is flooded. Low temps also cause them to not open. It's almost as if they tend to open when the bees and other main pollinators are most likely to be out and about.

@ joe jr

I am as thoroughly involved with my man garden as I possibly could be, so if the blooms would have opened, I would notice it! I am doing a human anatomy course that finishes in a few weeks, but despite that I still have been paying close attention. ESPECIALLY because of the thrip infestation I have been dealing with for the past week.

"Sometimes, the flower opens only for a very short period in the day, so it's easy to think it never opened if you didn't catch it"

- They never even begin to turn yellow as they should before they open, they only stay green as I pointed out. Unless they are wickedly sly and open up for only minutes, then there is no way I am missing them lol.

"I can't remember what nutes you are using or if you have mentioned it elsewhere"

- I am using FoxFarm trio nutrients, and I am currently using solely the bloom formula in conjunction with FF bigbloom. The FF Bloom formula is called TIGER BLOOM and has an N-P-K rating of 2-8-4. I use 2 tsp's per gallon of this, plus a Tbsp of the FF Big Bloom which is basically nothing more than a medium which prevents unwanted salt-buildups, and contains very little nitrogen (0.01 nitrogen rating).

ALSO: I have pulled apart a few of the flower pedals from the male flowers and rubbed them directly on the green "to-be-flowers" on the female organs but this has obviously not worked because they just die off regardless.

@homehydro

Good points lol. Sometimes I think things are going to be deduced, but this is not always the case.

Actually, yes. Cucumbers have been known to be quite wickedly sly. You gotta watch out for those things. Next thing you know they have those little tendrils around your throat and nobody can hear you scream.

In all seriousness, like I said, it is common for the flowers to all be male in the first week or so. Don't sweat it. Just keep some of the suggestions in mind in case a problem persists. Particularly the one about the insecticides and pollinators if you are using an insecticide.

Where are you at and what's the weather been like?

Lol instead of the killer tomato, its more like killer cucumber!

I'm in Springfield, Missouri and it has been hot, like mid 90's, and very windy here for the past couple of weeks and that seems to be deterring the bees and pollinators from my porch. Nothing along the lines of rain really. I hear from my father that Colorado has been getting hit pretty hard with snow/rain, and that Missouri is sure to see flooding soon.

Where are you @ joe? Hopefully nowhere that is flooding!!

I'm in Whiteland, Indiana just south of Indy. I went to school in Springfield for my senior year. Parkview High. Then I lived with some guys in a house just off SMSU campus for awhile. I got my start in gardening in Springfield, actually. Of course, I stopped that kind of gardening when I had a kid. . . I loved it out there.

Haha very nice! Wow, it is a freaking small world isn't it? That is so awesome that you have lived here before! I am actually going to MSU now (or as you and everyone else refer to it as, SMSU).

That is pretty much the same reason I first got into gardening myself too actually. Grew out of it as well. Springfield is a pretty awesome place to live, but sometimes I feel like I wanna branch out from here at least for a decade of my life. Life is good in the big S though! Unfortunately the only hydroponic store out here went under, probably due to bad business practice. Very sketch place, didn't even provide you with receipts and prices would change from the very minute you talked on the phone, to an hour later when you walked in the store. Lets see anything cool about town of recent.... oh yeah! The Springfield Cardinals team started up again and they built a killer new stadium downtown :D

So why did you decide to move? Family, etc?

Yep, family. I grew up here.

Just thought I should post some new pictures of my cukes........ sorry for the huge pictures, photobucket is difficult sometimes

Look at those beautiful roots : )

Ya, those definitely look like nice roots. The plant foliage and cucumber looks good as well. Were you able to come to any conclusions on why the flowers weren't opening and falling off?

Thanks HH!

Yes, they continued to do the same thing and fall off for another 4 or so days. After that, they slowly started growing a few female flowers. Now I see about 3 or 4 new female flowers per day! I think that this ended up being impatience on my part. They just needed a little more TLC and time : )