You can have up to 6 additional email accounts in Comcast besides your primary account. Sign on to your primary account and click on the Users & Settings tab at the top of the page. You should see a link in blue underneath your user name that says Create Secondary User.
If you notice yellow leaves in other areas of the tomato plant, or the yellowing at the bottom is spreading upward, this could be a sign of disease, such as curly top virus (usually curly top virus will show signs of yellowing leaves that are curling up as well), Ringtop Virus, or other diseases.
Problems on tomato leaves can mean the onset of a disease, an attack from a tomato pest, a nutrient deficiency, or conditions that can lead to trouble. Healthy tomato plants have leaves that are green and evenly-colored. Look for these red flags on your tomato leaves to quickly identify problems. Black, brown, dark, or water-soaked spots.