Q&A – Yellow Splotches, What’s Going On?

Roger asks Annie:

Q Hi Annie,

In the attached photo, the outer edges of leaves have this yellowish splotching going on.  it’s mostly on one variety with very minor incidence on a couple others.  i’ve researched and can only find two possible causes, one related to ph and the other to various trace element deficiencies.  plants are in a south facing window with filtered light, same as others which are not affected.  any idea on what’s going on?

thanks.

A Hi Roger,

Thanks for your question.  I have some questions for you  :-)  

Do you happen to know the name of this variety?  And when was the last time you repotted it?
Annie  :-) 

A Annie,

I don’t know the variety name.  At least a year since repotting.  I suspect that might be part of the error in my ways,  although I have many others on the same repot schedule that are not so affected.

A Roger,

The plant looks healthy to me other than the haloing on the older leaves.  Based on what you’ve said, I would suggest you groom those older leaves off and repot this plant.  Most standards like to be repotted every six months or so.  I did, however, run this by Joyce and she came back with more information.  Here is what she said:

“This splotching or haloing is probably related to excess fertilizer salts in the potting mix and by extension in the leaves. The salts draw water out of cells which are most exposed to air (around the leaf margin on the edge of the plant perimeter.)

Grooming would get rid of the appearance for a short time, but it is likely that it would continue to redevelop.

Leaching is an excellent solution to prevent a reoccurrence, by washing salts out of the soil. It takes time to do it properly. Ideally each 4″ pot should have about 2 quarts of room temperature water poured through the roots as the pot is turned so that all parts of the root system is flushed.

Here’s another possibility. Kent (Joyce’s late husband) fought this kind of haloing many years ago and the lab recommended that he add gypsum to the potting mix which worked wonders for his show plants. I’ve since learned that gypsum is best used when pH is neutral, magnesium is high and calcium is low. That’s probably too complicated for the average grower to figure out. But it is worth a try and it is fairly inexpensive. Kent used a scant 1/2 tsp gypsum per gallon of soil. Gypsum is often used on grassy areas near sidewalks which have been salted during icy conditions (Good way to use up the bag…)

Individual varieties varied a great deal for Kent in how they were affected. He had one variety from Lyndon Lyon (I’ve forgotten which) that would only show the damage in the outermost leaves. As soon as those leaves were removed, it would show up in the next row. The only way to show it was to groom off the leaves in the entries area. A week later, it would be showing up again.

Anyway, that’s my best guess. The real solution is probably best determined in a laboratory.”


I hope this information helps you,
Annie  :-) 



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