Always note the days to maturity on your vegetables and note that on a calendar. Whenever you think your veggies should be getting ripe, count the days and see if you are right. Sometimes cloudy days will subtract a day or so, or a cool snap, but basically the days to maturity is the days to the first ripe harvest. Probably you are just anxious for that first juicy 'mater ;)
Here is a good link to varieties and DTM's:
Why aren't my vine tomatoes turning red?
It depends on the variety of tomato and how long it takes to mature into a ripened fruit ready to eat. Some, like 'Early Girl' or 'Early Boy' types don't take as many weeks, while others take up to 75 days or more. As long as you are getting a good crop of green fruit, patience will prove you will have a bumper crop.
Just remember to water regularily; if they go through a 'dry' period and then you water generously, the tomatoes will split their skins and be vulnerable to rot and bugs.
Reply:Too hot, try giving water or pick green and let them ripen in the house in a window with sunshine.
Reply:I love Answers! I had never heard of the Heat Units deal, and I've been a gardening professional for a very long time!
What I would tell people in the greenhouse is like what the others have said. Note the maturity timing on the varieties you planted and when you planted them. That will give you a countdown for that first ripe one. If you have plenty of greenies, you'll eventually get the ripe ones.
Reply:You have all good answers but large green tomatoes are good sliced battered and fried.
Reply:Tomatoes take a certain amount of heat units to ripen. Look up heat units on the internet.
Farmers rely on a simple weather measurement called "Accumulated Heat Units." It's revealing to note what this tells gardeners about conditions west of the Cascades. To figure the Accumulated Heat Units, or AHUs, keep track of the daily mean temperature between April 1 and October 31, an average growing season for edibles. If the temperature exceeds 50 degrees on a day, the AHUs are calculated as degrees over 50. For instance, a mean temperatures of 55 F. would yield AHUs of 5 for the day, that is 5 over the 50 degree mark.
How this relates to crop success is simple. Most crops require a specific ideal minimum of AHUs for productivity. On average, the AHUs in the Seattle area are only about 1800 per growing season; in the Bellingham area, they are only about 1330. To put this in perspective, PACs in eastern Washington has an average of about 2600 AHUs, even though they have many fewer frost-free days than Seattle. To ripen many grapes, for instance, AHUs of over 2200 are a necessity. Variety choices are the key.
Tomatoes, for instance, one of the most popular vegetables for home gardens, can resist ripening unless the plant choice is adapted to cool conditions. A few that have been proven to taste good and produce well are "Stupice," "Oregon Eleven," and "Fantastic." Cherry tomatoes ripen well here and many gardeners do well with "Sweet Million" and "Sweetie."