Help Plz My Plants Have Deficiencys bad

Today o went in grow area and my plants have brown spots and tips are brown n crispy I was told I had n tox and then was told it was cuz they needed nitrogen what can I use to help with yellowing leaves and brown spots that I can get from Lowe's or home depot until I can order some better nutes thanks for any info thanks

Get a better pic of the whole plant.

It looks hungry and over watered bad. Looks like pH problem from poor watering habits.

looks like calcium and a bit of magnesium deficiency. got Cal/Mag? use it. GL

Well I only water it ever 4 days but only if the pots feather lite and I do got cal mag I'll try to feed it with it and tiger bloom I got Epsom salt and fish emulsion also I guess this is what happens when I use pro mix when I used ffof they never got this bad thanks for info

Could be sun spots, ru spraying with a foliar?

No just regular watering and I use my pH pen its only a cheap one but its always between 6.5-7