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.
A typical grow takes about 85 days from seed to harvest, but that number can vary quite a bit depending on what strain you're growing and how long you keep the plants growing vegetatively before flowering them. If you want to minimize calendar days of grow time, you can select early-maturing strains for growing.