My husband and i are traveling to Rome and Florence in June. We arrive at 7:45 am in Rome and were planning to take a train immediately to Florence, last night I tried to get a train reservation on the Trenitalia site for our train to Florence and the only one that came up is late in the afternoon. Did I wait too long? I assumed from the messages posted here that there were numerous trains during the day. Am I doing something wrong or did I just wait too long? Thanks for the info.

You probably didn't wait long enough. Reservations for most trains open two months in advance. On some of the trains between Roma and Firenze, reservations are optional, so these will always be available. Most people don't book train journeys a long time in advance, so it's very unusual for a train to be fully booked more than a few days in advance.

Did you reset the time and date? If not, Trenitalia will only give you the trains for the day and the time you signed on.

And, as GeoffHamer has pointed out, you can only book 60 days in advance.

Thanks! I didn't realize I needed to wait.

Yes, you have to wait to book but like Eloise says, you need to reset the time. You should be able to see all trains that will be available on that day if you set the time correctly.