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.
Knowing how to tell when carrots are ready to harvest is important for getting a good crop. First, consult your seed packet to see how many days it takes your chosen variety of carrots to mature. Baby carrots are usually ready to harvest 50 to 60 days from the planting date. Mature carrots need a few more weeks and are usually ready in about 75 days. Most carrots are ready to harvest when the shoulders are 1/2 to 3/4 inch in diameter, but again, there is much variation depending on the variety.