Chemical Weathering. Chemical weathering takes place in almost all types of rocks. Smaller rocks are more susceptible, however, because they have a greater amount of surface area. Chemical reactions break down the bonds holding the rocks together, causing them to fall apart, forming smaller and smaller pieces.
Autos generally are ready to harvest sooner than photoperiod. Most autos are ready to harvest 65-90 days after being sprouted from seed. Some super autos have been bred to grow very big and can take up to 100 days before harvest.
This type of okra is ready to harvest in 50 days to 64 days, so you're approaching that zone. You must have had some nice growing conditions! Harvest pods when 3 inches long for the most tender, flavorful okra.