Average last frost date between March 20 and April 6. That is the difference between south Atlanta and Cartersville. I haven't seen a listing for Kennesaw yet.
For what can be planted outside when:
Very early spring (as soon as the ground can be worked)
OnionspeasspinachEarly spring
lettucebeetscarrotsradishesdillcilantrocabbagebroccolicelerykalepotatoesAfter last frost date
beanscornmelonscucumberssquashtomatoespepperspumpkinseggplantbasil