Fertilizing Cucumber Seedlings - Don't

This year is the first year I've had much success with seedlings.  I tried last year, but my little plants were miserable because I didn't know what I was doing.

This year, I have been much more successful, but I'm still learning from my mistakes!

I decided to give my plants a little fish fertilizer because I watched another gardener do it in his video for his tomato plants.  Mine were still kind of small, the leaves seemed to be withering, so I thought maybe they needed a little food.  It helped the tomato plants a little....

Afterwards, I read that it is not necessary to give seedlings fertilizer until they are more mature.  I was giving it to all of my seedlings and it especially had a negative effect on my cucumber seedlings.  I won't do this again!  Compare the dark green leaves with the yellow-green leaves.  Half the seedlings are dark green, the other half are yellow-green.  I did decide to put some of the yellow-green plants in the garden, but I am also going to put in some seeds to start some new plants.