Originally Posted by Pat Kiewicz

GardenCadet said:
My tomatoes have cropped really well this year and have generaly ripened
nicely but have suffered a bit from greenback, which has also affected
the flesh inside the fruits. This has resulted in areas of green rather
inedible bits around the stalk area, which have to be cut out before
eating. I am wondering what might have caused this, what I can do in future to
avoid it?

My own experience is that green shoulders and large green cores are
common in some varieties and very rarely occur in others. In a large
oxheart, it's no big deal to cut away the top and cores because you
still have a lot of tomato left. In a small variety this can cost you
most of your fruit. Some catalogs will admit that a particular variety
is prone to green shoulders, and heirloom varieties are more likely to
have this problem than modern hybrids.

Here goes with some other explanations (though I firmly believe that
varietal traits are the most important factor causing green shoulders).

Various sources say that green shoulders are cause by high temperatures
and sun exposure.

According _Identifying Diseases of Vegetables_ by Penn. State Dept. of
Agriculture "blotchy ripening" is "promoted by low light intensity (a
condition prevalent among dense vines), low temperature levels, excessive
soil mousture, excessive soil compaction, high nitrogen levels, and low
potassium levels."
--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)