Tomato tops are yellow

[Just Whisper]

I have 40 tomato plants, about 4 different varieties, growing in containers. They were doing great until they slowly started getting a disease. I have managed to keep the diseased foliage removed and am pampering them to stay alive. So far so good. They are all loaded with tomatoes. My problem is that no matter how long I leave the tomato on the vine the top of the tomato will not ripen. It stays yellow, and the inside is white on the top. The rest of the tomato is bright red, juicy and sweet. If I try to wait for it to ripen the tomato will rot first. Do I have a nutrient deficiency or is it the blight causing this? Of all my years growing tomatoes this is a new problem to me. As you can also see in the photo several days of rain caused most of them so split. So sad.
[img]https://i245.photobucket.com/albums/gg54/Just_Whisper/tomato.jpg[/img][/img]

[GardenerGirl]

It looks to me like this could be a form of greenback, where part of the tomato just doesn't ripen fully. Too much strong sunlight can cause greenback: has it been overly sunny there? If so, you might try shading the tomatoes for a few hours each day.

Otherwise, you could try testing your potassium and phosphorus levels: if they're low, your plants will be more prone to greenback. Try fixing the heat problem first, though, if it exists. It's a safer approach.

On the bright side, greenback isn't at all dangerous. Just cut off the unripe part and the rest of the tomato should be perfectly good.

[Just Whisper]

Thanks. I have been doing just that, and the ripened parts are so yummy. I live in Fl and they are on my back patio where most of them get full sun from about 6am till about 6 pm. Some of them are in the shade of the overhang for most of the day. I will have to compare them to the full sun plants and see which are doing this the most. I have never heard of that, greenback. I will also check the nutrient levels. thanks so much. I'll post back when I get it figured out.

[sweet thunder]

I've heard it called green shoulders, and some varieties are more susceptible than others.
Aside from providing more shade you can also pick them green and let them ripen off the plant.

[rainbowgardener]

agree with the greenback/ green shoulders posters. Colorado state U. extension has a nice webpage on recognizing tomato problems at

https://www.ext.colostate.edu/PUBS/Garden/02949.html

Here's what they say:

Green/yellow shoulders develop on ripening fruit, possibly due to high temperatures. Chlorophyll in this area is slow to break down and results in a patch that remains green or turns yellow but not red. This problem may affect the entire shoulder or only a small, irregular patch. Shade the plant and take other precautions to reduce the fruit's exposure to the sun.

[Just Whisper]

More good suggestions. Thanks all. I will see what I can do about providing shade. I may have to erect my portable canopy and try to squeeze them all under it. Right now they are 3 deep all the way across the back of my house on the pool patio. Only the ones against the house get shade. This will take some doing on my part, but I will prevail. LOL

[GardenerGirl]

I'm not sure if this is helpful, but after re-reading the thread, I wanted to mention it. The blight you mentioned in the first post probably did contribute to this, albeit indirectly. Tomato leaves love sun and heat, but the fruit are fairly sensitive, and don't do well with direct sunlight as a rule. Once you started cutting away diseased leaves, you probably exposed the fruit directly to more sunlight, which may have caused this.

I've never directly tried this, but I've heard some people have success, in situations like that, rigging little covers to fit over their tomatoes, shielding the individual fruit from the sunlight in a way similar to how the leaves would ordinarily do.

If getting more shade over the whole plants won't work, you might consider this for those plants that are producing more fruits with greenback.

[Just Whisper]

You are probably right about the lack of foliage. In fact I hadn't even realized until today how much of it I have had to cut back. I would say about half of it over a 3-4 week period. Good call there.

[Gary350]

I use to have that problem when I depended totally on mother nature. Now that I fertilize my tomatoes with 15/15/15, Ammonium Nitrate and Lime I never have that problem any more. My tomatoes get full sun all day, 90+ degrees in July and 100+ degrees in August.

Do an experement feed your plants some potash and phosphate and see if the problem clears up. I have 40 tomatoe plants too, I mix a cup of 15/15/15 in 5 gallons of water and give each plant a quart of water once a week. You might give that a try to see if it solves the problem. I feed my plants nitrogen too that produces a lot of leaves that makes a lot of shade for the tomatoes. Do an experement fertilize 1/2 the garden and shade the other 1/2 to see which one fixes the problem.

[Just Whisper]

Thanks Gary. I do fertilize my tomatoes about every two weeks. I may need to step that up since they are having a hard time. I am going to do a soil test today also just to see what they are missing the most.

I have actually been to Murfreesboro. I use to have a dog that I could not keep and a friend of mine found a home for him on a farm in Murf. That was when I lived in VA many years ago.

Thanks again all, for your suggestions and help.