cucumber leaves changing colour

[Marty007]

hi all
my cucumber true leaves are going light green(well 2 anyway) they are all under the same light, in the same pots and watered and fed the same any suggestions google as always has a million reasons thanks photo attached

 

[Chuck]

It appears that your plant is in the first stage of chlorosis. Even though you fed your plants the same this particular plant for some unknown reason, is unable to uptake enough nutrients or it needs more nutrients. No two plants are exactly the same because of their genetics, their DNA. It looks as if it is a nitrogen deficiency because the yellowing is more or less even over the entire leaf and not just between the veins of the leaf. If the veins stay green and the area between the veins yellows it is a micronutrient deficiency, probably iron. I would just feed the plant more with your fertilizer and if that doesn't fix the problem I would give it mineral supplements such as Chelated Iron.