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I've been experiencing some yellow shoulder and uneven ripening of some of my tomatoes and so I started doing some digging on the problem. It's not something I had to deal with up north. I'm sure people experience it up north; it's just that I didn't until I moved to the Deep South.

Anyway, I came across a document that I found quite interesting and I want to share the information with ya'll.
https://extension.umd.edu/sites/default ... matoes.pdf

It deals mainly with BER and yellow shoulder/uneven ripening, but it has good info in it. I always felt like the soil test was the end-all thing. Turns out, it's not.

It looks like the report was mainly for the market grower, but still several useful items could be gleaned. Soil testing is important but as one piece of the puzzle. Balanced soil conditions, proper and timely watering, temperature and weather conditions, a good mulching program and choosing varieties for the area are important aspects to having a good result.

You cannot always control the weather (well, never), you can make sure your soil is in proper balance (this you can do with help from soil testing), you can avoid overhead watering (except for when it rains), a mulching program of any kind is better than none and that will help control soil temperatures and moisture retention. Varieties that do better in certain areas than other locations is more conjecture than not, but by researching some of the tomato growing sites you can get a pretty good idea what does well in your area.

My Nebraska favorites may not so well on the gulf coast but there are plenty of folks who would be happy to accommodate you with that information. It was a sharp learning curve for me when I moved from central Iowa to eastern Nebraska and that was only a couple of hundred miles. Good luck in your garden.

Yes, all those are good suggestions. I have my problem under control. I just wanted to share that information.

Interesting read! The importance of soil temp and substantial amount of potassium were a couple of new info that caught my eye.

Thanks Allyn.

Exactly! I had black plastic on all my containers. I'm switching to white and I moved some of my plants so the plant gets sun but the container is shaded. I know small containers can have a problem overheating; I didn't think that would be a problem with 27- and 33-gallon containers. And the plants themselves look good. It was only a fruit problem.

My problem was the soil in the containers getting too warm. I had these two plants side by side -- one was giving me good tomatoes and the other was giving me tomatoes with yellow shoulders. The yellow-shoulders container was in front of the good-ripening container so it was getting full sun all day and shielding the other container from the afternoon sun.

It was interesting that the soil test can show adequate or even an overabundance of something, but the plant won't utilize it and will exhibit deficiency symptoms because the soil is too warm. I know it can happen if the soil is too cold, but the soil too warm was new info for me and information I definitely need living in the Deep South.

Interesting read. I have had green shoulders but never yellow. I use potting soil so I actually don't test that but I guess it is working. The tops of the tomatoes are in the sun but the pots themselves are shaded by other plants around them.

Thanks for sharing this! Very interesting.

I noticed something that they didn't really comment on. The chart on p. 22 shows high phosphorus, low potassium, and very high sodium (4X the top of the normal range). In living cells, K+ and Na- are the basis of ion transport. They interact and they need to be in balance. (When you hear people talk about electrolyte imbalance, which can be a serious condition, they are usually talking about K & Na.)

With antagonistic physiological effects, potassium and sodium both contribute to maintaining homeostasis within your b
ody. The main link between potassium and sodium is that they both perform many of the same body functions, such as muscle contraction and fluid balance, however they usually do so in an opposing manner. For example, sodium draws fluid out of the cells, increasing blood pressure, while potassium draws fluid into the cells, decreasing blood pressure. Additionally, sodium intake can affect potassium excretion from the body, just as potassium intake can affect sodium excretion. An increased intake of one mineral will result in an increased excretion of the other mineral.

https://healthyeating.sfgate.com/sodium- ... -1113.html

Thus having high sodium, essentially "uses up" potassium to counteract it. So it seems to me that one of the problems that they didn't mention is high salt levels in the soil. This can be a result of repeated use of synthetic fertilizers.