Light green/dark green splothes?

[greenpassion]

Wow. Here I go with yet another issue. I have 13 phals that are growing under my led track light garden (from Orchid Web)
I have had them here for ages, with no problem. A few months ago, I had noticed that one of them had 2 leaves that were developing areas of a lighter green. Around that time I changed fertilizers from Dyna Gro to MSU for well water. And as soon as I made the change, the new growth was all uniform in color. It's put out 3 solid green leaves since.( The ones that were splotchy were the ones close to the media.) I have read here that when plants are lacking in nutrients, often they will develop this color issue. That said, yesterday, as I was watering, I noticed that another one is doing the same thing, but not older lower leaves. These are newer leaves. I will post a pic, but I don't really think it'll show the discoloration, as it's not glaring, but more subtle.

---------- Post added at 02:40 PM ---------- Previous post was at 02:20 PM ----------

I meant to add that I have them on a heat mat, which I had not turned down when it got hotter here. (Vermont) So could it be they are too warm?

[estación seca]

Of the different things it could be, I might start with magnesium deficiency. There is one atom of magnesium in every chlorophyll molecule. Without adequate magnesium plants aren't the proper shade of green. In magnesium deficiency, this shows up on newly-developing leaves, because more chlorophyll is being made there.

Perhaps consider supplementing your Phal's non-fertilizing watering with Epsom salts. I don't have good information on how much to use, but a teaspoon / 5ml of powder per gallon / 3.78 liter of water is probably a good place to start.

It can take a while for plants to get enough magnesium to correct a deficiency, so keep at it for a few months at least.

[greenpassion]

Thank you for your reply. But the newly developing leaves are the normal ones. The splotchy light green dark green is happening on Lower leaves. As a firm believer in MSU fertilizer I doubt it is a nutrient deficiency. I'm wondering if it's too much light as I increased the brightness of the LED lights from Orchid web six months or so ago. Or the fact that I had the heat mat up higher for the winter months and now it is summer.. I would understand if New Growth was splotchy and older growth was healthy but this is the opposite.

[Orchid Whisperer]

e.s. gave you the most likely answer, andd the best/lowest cost solution. Epsom salts, teaspoon per gallon. Door is open if you choose to walk through it.

I used to have splotchy leaves, especially older Cattleya leaves. Not so visible when leaves were young. A couple years of regular Epsom salt use, no more splotchy leaves.

[greenpassion]

Ok, I'll try the Epsom salts. Another question. What would cause a mag deficiency when I've been using MSU fertilizer? Does that mean the it's lacking the proper amount of magnesium?

---------- Post added at 05:31 PM ---------- Previous post was at 05:25 PM ----------

I should add here that I make up gallon jugs of the MSU and feed at every watering. Would this be a culprit too? I feed a weaker solution than the 1tsp directions per gallon.

---------- Post added at 05:32 PM ---------- Previous post was at 05:31 PM ----------

I'll post pics as soon as I can.

[Dollythehun]

My phals had well water for years. Tested, it was within reason, not harmful, decent tds and ph. Yet something about it after awhile caused splotchy lower leaves. They bloomed regularly and grew nicely. I stumbled on the site for St AugustineOrchid Society nutrient deficiencies and it sure looked like I had a magnesium problem. I did as ES suggested, then started using quarter strength Cal Mag every watering. After months, everyone, except one, looks better. The new growth robs nutrients from the old, it seems. I'm too lazy tonight to send you a link but, Google it and see if it matches your problem.

[greenpassion]

Thanks so much! I will Google it, and take all suggestions here!

---------- Post added at 08:09 PM ---------- Previous post was at 07:36 PM ----------

Is there a preferred brand of Cal Mag I should get?

[Dollythehun]

I just got Dyna Gro from Amazon. But Epsom salts is cheaper.

[Orchid Whisperer]

Originally Posted by greenpassion

Thanks so much! I will Google it, and take all suggestions here!

---------- Post added at 08:09 PM ---------- Previous post was at 07:36 PM ----------

Is there a preferred brand of Cal Mag I should get?

Plain Epsom salts from the pharmacy for Mg and S, and gypsum (or plaster of Paris) for Ca and S. Teaspoon each per gallon. Add about a cup or two of this to your regular water. WAY cheaper than buying CalMag. But, if you don't mind spending the $$, there is no problem with the pre-made CalMag products. Any should be fine.

[estación seca]

My tap water is loaded with calcium. Maybe I should bottle it and sell it.