Hi Alex,
One thing to be sure to check is what color the seed packet says about color upon ripeness or what the picture shows. Usually a ripe tomato changes color from when it is unripe - even green ones! So when you think one or more of your tomatoes are ripe check for the following:
1. Does it smell ripe, i.e. can you smell that tomato smell vs how the ones you KNOW are unripe smell?
2. Is it shiny or glossy rather than the duller unripe ones?
3. Does it give a bit when you gently squeeze it?
4. Does it feel slightly heavier than an unripe one of the same size?
Hope this helps!
