While searching for why I have a lot of green tomatoes on the plants, but they are not ripening, I discovered this site that tells you just about everything you would ever want to know about them.
As for my problem, it seems that this is about the time each year (mid to late summer) a lot of gardeners get frustrated because their tomatoes won't ripen. They’re big and green on the vine, but they just sit there!
Apparently there is nothing’s wrong. Under normal conditions it takes about 50 days until a tomato reaches full maturity.
They are doing several things all at the same time: producing and ripening fruit, putting on new growth, developing root systems and making components for color and flavor.
When conditions are ideal (favorable climate, plenty of spring showers and moderate summer temperatures) the plants thrive and the tomatoes ripen quickly. But, when the weather quickly becomes hot and dry the plants are faced with demands that change how their energy is distributed.
The key starts with sufficient leaf surface. When plants become laden with tomatoes additional foliage surface area is needed to keep up with these increased demands so even though tomatoes reach full size in about 25 days, they don't completely ripen until sufficient compounds are present to give them the color and taste we are looking for.
Air temperatures above 85 degrees will slow down ripening because above that tomatoes stop making carotene and lycopene pigments, two of the most important. Also, the temperature below the ground is important. The roots require soil temperatures below 80 degrees for optimal growth and if the below ground temperature is higher than that, more of the plant's energy is directed to developing a deeper root system. This is another factor that contributes slow ripening.
One tempting “solution” is to add more fertilizer, but that's a BAD idea. It'll exacerbate the problem by forcing the plants into a growth mode.
I am assured that they’ll adjust in due time. And, since my plants have a lot of green tomatoes, the recommendation is that I pick some of them so there is less demands on the plants. And...be patient. Being patient is the hard part because, now that my cilantro is ready, I'm ready for some home made salsa.