Anyone who has ever grown tomatoes knows there is an endless cavalcade of problems waiting to afflict them. That makes it all the more frustrating when you manage to grow a healthy tomato plant full of luscious tomato fruits that show all the signs of being ripe, except that the area near the stem refuses to change color.
Identifying Green and Yellow Shoulders
When the stem end of a tomato remains green or yellowish, it is aptly called "green shoulders." This is different from tomatoes that merely haven't finished ripening. With green shoulders, the green area is noticeably firmer or harder than the ripened part of the fruit. It's easy to spot on tomatoes that change from green to another color, like red or yellow, but it can also occur on tomatoes that remain green, like Aunt Ruby's.
In some tomatoes, like Cherokee Purple, it's normal for the stem end to remain a little green even when they are fully ripe. You can identify green or yellow shoulders by checking to see whether the stem end is not just the wrong color, but also hard to the touch. And if you happen to bite into one, you'll also notice it doesn't taste as sweet.
Causes of Green Shoulders on Tomatoes
Normally the chlorophyll in an unripe tomato starts to break down at the blossom end and continues around and up the fruit. Green shoulders occur when the chlorophyll either does not break down as the fruit ripens or if it breaks down too slowly. This can occur for a couple of reasons, both weather-related. First, green shoulders can be caused by too much direct sun exposure. It may also manifest when temperatures remain high for a prolonged time.
Yellow shoulders are not caused by the same problem. If the stem end of your tomatoes remains somewhat yellow, it means the fruit was unable to produce lycopene, the pigment that gives tomatoes their wonderful antioxidant properties as well as their red color. Lycopene production slows down when the temperature gets warmer than about 75 degrees Fahrenheit. Thus, the cause is similar to green shoulders, but a different pigment is responsible.
Eating Tomatoes With Green or Yellow Shoulders
While green or yellow shoulders are hard and unpleasant tasting, the rest of the tomato should still be delicious. Just cut around the hard, unripened top and eat away. It takes more than a little inconvenience to render a homegrown tomato inedible.
Preventing Green and Yellow Shoulders
Once you notice green or yellow shoulders appearing on your ripened tomatoes, it's too late to correct it. Like blossom end rot and cracking, once the final symptom appears, there's nothing to be done. You can, however, take a couple of steps to try to prevent these shoulder problems before they occur.
Make sure your tomato plants have plenty of foliage to shield the tomato fruits. Although tomato plants love heat and need plenty of sunshine to ripen their fruits, the sun doesn't have to shine directly on the fruits themselves. If you are having a particularly hot summer, the fruits will appreciate some cover. Go easy on pruning your tomato plants.
Choose Hybrids Rather Than Heirlooms
Choose tomato varieties that are less prone to the problem. Green shoulders seem to affect more heirloom varieties than hybrids. Not all heirlooms are prone to it, so don't give up on them entirely. You probably won't find tomatoes labeled as resistant to green or yellow shoulders, but you may find descriptions that tell you when a variety is prone to it.
Pick Tomatoes Early
If you're having a hot summer and all your tomatoes seem to be struggling with shoulder problems, you can try picking them when they are just starting to blush red and bring them out of the sun to finish ripening. Unfortunately, you may be compromising some of the vine-ripened flavors by doing this, so it's only for extreme cases.