Bert Hyman said:

Because of a cold wet spring, the tomatoes are just now coming in.

In many of them, the flesh around the stem is yellow/green and hard.
The online plant problem Web sites say this is due to too much sun and
that the remedy is to shade the plants.

It's very much connected to *variety.* Some varieties are genetically
prone to green shoulders. Others are resistant.

As a specific example, two very early tomato varieties that other wise
looked and tasted remarkably the same (when I grew them side by side):
'Stupice' (an heirloom) developed green shoulders as the summer went
on when '4th of July' (a hybrid) did not.

Some of the old heirloom oxheart-types I've grown have had massively
green shoulders, while others have not. We've had an exceptional
amount of sunshine in the last month and a half. Of the varieties
I'm growing this summer only one of them 'Juliet' is showing any sign
of green shoulders (tiny ones). I'm growing 'Juliet' mainly for drying
so will just cut the green parts when I halve them.

However, our neighbor's maples have grown in to the point where we're
only getting 2 to 3 hours of direct sun per day, so I have a hard time
believing that's the problem.

On the other hand, the plants are in a corner formed by two exterior
walls of the house which is like a little solar oven; it gets pretty
warm in there during the period we do get sun.

Could the problem be heat, and not light?

Do they start getting sun only in mid-day (the very peak of insolation)?
It could be the timing of the sun exposure, though the heat is very likely
a part of it.

Any other avenues to investigate?

Low potassium can cause blotchy ripening.

Found this, from the Royal Horticultural Society:

"Disorders of fruit are common; greenback, where hard, green areas
develop on the shoulder of ripening fruit, is usually caused by heat
injury and insufficient potassium. Good ventilation, shading, use of
tomato fertilisers and choosing greenback-resistant cultivars will help
avoid this."

http://www.rhs.org.uk/advice/profile...toproblems.asp

Well, there you go then...
--
Pat in Plymouth MI ('someplace.net' is comcast)

After enlightenment, the laundry.