Yellow leaves on the bottom

Definitely looks the a deficiency and based on the location its one of the mobile nutrients. A good way to narrow it dow is to first figure out if its a mobile nutrient or immobile. If the effected vegetation is new growth it's generally immobile because if it's a mobile nutrient the plant will take from older leaves what it's laking to support the new growth. From there you look at what part of the leafs effected and what its effected with. I will inbox you a great chart that I found to help you out. in my opinion this is a nitrogen deficiency growmie.