would this be this nitrogen deficiency...

Definitely looks like a N issue, though there also seems to be other symptoms present as well.

At first glance I would start with checking the roots for crowding. That is a pretty small bucket for a plant that size in soil. Second, check for drainage. The curling leaves suggests an overwater condition. IF the plants are rootbound and the pots not draining properly, this can cause what we see here.
Your 3-1-3 should be fine for veg... The numbers are not specific quantities of each in the mix, but ratios... Your ferts have a ratio of 3 parts N to 1 part P to 3 parts K... No different than 30-10-30 or 15-5-15... The higher numbers are not stronger, just a different way of listing the ratios.
That being said, IF you don't have drainage,and/or IF your soil holds too much water, and/or IF your plants are rootbound, and/or the rootzone is unhealthy, then we see a combo issue like this.
Think about the possible issues presented and let us know if you feel that any of them could be happening.

 

Transplants that are gentle and don't disturb the micro-roots will have virtually no negative impact on your plants.
Don't try to remove excess soil from the rootball, just gently place the ball in a large pot and pack the soil around it.
If you do this right, the plant won't complain at all.

 

Same answer, different thread. ... Usually just ask for second opinion and someone will chime in... I'm glad someone second-ed my advice . Good luck.