Yellowing cucumbers

My cucumbers have started to yellow from the ground up. I planted them out into the greenhouse beds about a fortnight ago, four lovely healthy plants now 3 are yellow nearly all the way up only the top shoots are green. They are in a heated greenhouse but I've not shaded it yet.
Any ideas?
 

I had the same last year and found some fat bugs chewing through the stems just below ground level Put them in pots the next time and they were alright then it's a pain tho

Are they planted a bit "raised"?

Stems are very susceptible to basal rot, so having them in a bit of a mound, and not planting them deeper than the original pot, can help get the water to run away from the stem.

Sorry, I'm sure I am stating what you already know ...

I don't prick mine out deep either - on the basis that the stem from seed to seed-leaves is designed to be buried I leave that above grown in the hope that it is tougher than the normal growing stem above that point.

When i bought my new water butt yesterday from Wilkinsons i had a look around and was surprised to see cucumber seeds for 99p i also paid £4 for my packet, that was my first trip to Wilko's but i reckon i'll be back soon.

My cucumbers have started to yellow from the ground up. I planted them out into the greenhouse beds about a fortnight ago, four lovely healthy plants now 3 are yellow nearly all the way up only the top shoots are green. They are in a heated greenhouse but I've not shaded it yet.
Any ideas?
 

try a pinch of sulphate of ammonia around the base and water in.