Question: How can I tell by size, color, and firmness when it is time to harvest my tomatoes?
Answer: Leave your tomatoes on the vine as long as possible. If any fall off before they appear ripe, place them in a paper bag and store them in a cool, dark place (never refrigerate or store on a windowsill). The perfect tomato for picking will be very red in color, regardless of size, with perhaps some yellow remaining around the stem. A ripe tomato will be only slightly soft.