Cucumber Help

This is my first time (attempting) growing cucumbers and I need a little advice.
I've got the Pepinex All Female type and well here goes...
There has been lots of potential fruits but only 1 big one. The potential fruits just seem to wither and die.
So what am I doing wrong?

 

Are you watering consistently, not morning one day evening the next, and a good amount as cucumbers are 99% ish water,also feeding every week,

 

No Pam, i only water it every few days...

 

try every day as they do need a lot of water, i am assuming they are in pots in a greenhouse ???

 

They are in pots in a conservatory. Am I suppose to pinch them at any stage?

 

No they need stakes and support ,don`t forget to feed

 

Fed today and watered yesterday!

Now for the daft bit . . . how do you know when to pick them?

 

it`s not daft ,it`s quite hard to pick at it`s best. Read your packet see what size they say they will get to, I had some the skins were very spiky ,as they grew the skins got smoother.when you think it looks ready try one ,if you feel it`s not quite ripe leave the next one a day or two longer,and vice versa pick sooner if you think too ripe,you are looking for crisp and tasty, and a nice dark green colour.

 

There is no packet, i bought them as little plants...It was spikey and now it's gone quite smooth it maybe the time!

 

I'm not sure, but I think Pepinex are a small variety?

 

Pepinex are full size cucs and should make up to 12" to 14" when mature. You should be able to judge when they are ready as they'll be quite firm and smooth.
As has already been said keep the plant moist (but not wet or you risk basal stem rot) and feed regularly. If you pick the mature fruit as soon as it/they are ready it will help the plant divert energy into developing more fruit.