Early Girl is a tough grow in high heat. Not always but generally the lower leaves yellowing and droping is a mag problem. Epsom salt and some good 3-5-4 or any organic balanced tomato food usually brings them back. In general tomatoes feed N-P-K pretty much like weed going to flower. Just a weaker concentration of nutes.
I had some early girl this year hit by the drought watered and fed every day and still some lost every leaf. Bare stems with what looks like grape tomatoes is not a pretty sight. Covered with agrabond 15 Mine are coming back but cold is only a few weeks away. So?
Tomatoes are much harder to grow than weed is. Too many things blown in by the wind that you cannot see or smell that will wipe them out. A neighbor, a mile away, who developes a fungus may get you.
Good Luck