Nutrient deficiencies

[Dollythehun]

Last night was football and I was left to my own devices. While surfing the net, I found pictures of nutrient deficiencies and realized I have one, maybe two. Magnesium and calcium. Since we have so many new members lately, I've included a link to the article and I also would like to have some input on your fertilizer picks.

Orchid Environmental Damage

We have very hard well water, lots of iron. Hot water is softened. Cold water is not. So, we filter our water through a Pur filter. Now, I also filter that water through a Mavea pitcher. I noticed some time ago that if I used tap water, my orchid tips turned brown, then I noticed this leaf mottling. I realize I could use epsom salts, which I will but, my fertilizer says it has magnesium added. I think this could be an interesting and valuable discussion.
Dolly

[Fernando]

I wonder if anyone of us has seen a calcium deficiency in orchids.

Chlorosis can appear on lots of occasions, and mostly not because of nutrient deficiency, but because of under optimal environmental parameters, read: not sufficient light in winter, suboptimal tº (too cold), humidity stress (too low rH).

[jkofferdahl]

That's an interesting link! I noticed that it also mentioned ferns, a topic of a couple of other threads here. It once again confirms that's if a fern is found growing with an orchid it should immediately be removed, and ferns are NOT good growing companions with orchids.

[estación seca]

Tap and well water varies dramatically in mineral content and acidity/alkalinity around the country. New Yorkers can use their tap water on their orchids with great results. My tap water is good for killing orchids. It just isn't possible to discuss water without having an analysis at hand.

Municipal water supplies in the US are required to post their water analyses on line each year. (I've looked it up for places in Canada, Singapore and several European countries, as well. Here are the analyses posted by the City of Phoenix, Arizona: https://www.phoenix.gov/waterservice...uality-reports )

In general water is "hard" because it has a lot of calcium and magnesium. Have you ever had an analysis done on your well water? I would want that done before I drank it. If your water is high in dissolved minerals, that alone could be damaging your orchid leaves. This is measured in Total Dissolved Solids or TDS, measured in parts per million or ppm. Most orchids don't want TDS over maybe 200-400 ppm or so, some up to 600. Slippers need much purer water, maybe not over 50-100 ppm.

I have no idea what those pitcher filters do, but my best guess is just about nothing. (They may provide a reservoir permitting water-borne bacteria like legionnaire's disease and fungi like black water mold to grow in the filter.) They almost certainly don't affect the mineral content nor pH of the water.

Most water softeners take calcium out of the water and replace it with sodium. This is very bad for plants and not good for mammals, so softened water should not be used for plants, pets nor cooking. A few people have softeners that use potassium instead of sodium. This can be fine for people and sometimes for plants, depending on how much is actually in the water. Again, water analysis is necessary.

Plants absorb minerals differently at different levels of pH (acidity of the water.) Too far in the acid or alkaline direction and the nutrients are not as soluble in the water/soil solution. Also, plants don't absorb minerals well at the wrong pH, even if the water is loaded with them. This is one reason plants don't get much calcium from hard and alklaline water - it isn't very soluble at alkaline pH, and plants aren't able to absorb what little there is at an alkaline pH.

Same with iron. A lot of soils are loaded with iron, but plants can't absorb it at alkaline pH. (Nor can we. Antacid use can lead to iron deficiency.) This is why acidifying water and soil is an easier way to correct chlorosis in a lot of landscape plants than is providing more iron, and adjusting orchid water pH closer to 6.5 than 8 will lead to much more calcium and magnesium absorption than adding it to fertilizer.

Magnesium is the business part of a chlorophyll molecule. Iron is a co-factor in synthesis of chlorophyll. Deficiency of either can lead to yellowing leaves when not enough chlorophyll is synthesized. The yellowish patterns look different; iron deficiency yellowing is primarily seen along leaf veins, and magnesium deficiency is all-around yellowing.

[Dollythehun]

Sigh. Yes, we had our water tested, we live close to a landfill, so when we bought, we had it tested. Probably need to do it again.

However, our iron uptake is poor due to the reasons you listed. Normally, I would put actino iron in the potting soil but, orchids are not in soil. My discoloration is mottling, I know the difference.

My point in the OP was to present the link and get some fertilizer suggestions. As to my drinking water, it's filtered from the fridge. I don't want RO because I don't want to run the pump that much. (Btw, for my age, I am in excellent health, I try to drink more wine than water&#128518.

Now, back to the original question...

---------- Post added at 07:47 PM ---------- Previous post was at 07:37 PM ----------

Originally Posted by Fernando

I wonder if anyone of us has seen a calcium deficiency in orchids.

Chlorosis can appear on lots of occasions, and mostly not because of nutrient deficiency, but because of under optimal environmental parameters, read: not sufficient light in winter, suboptimal tº (too cold), humidity stress (too low rH).

Yes. I agree. I had been looking at temp and light and that did not seem to be the reason. This was a good link with pictures...

[estación seca]

Your water shouldn't change much over time. Do you have the analysis? Do you know the TDS, the pH, the total alkalinity, the hardness?

Note: almost all Florida has exceptionally alkaline water with high amounts of calcium. But it's not available due to the pH. Recommendations at the St Augustine Orchid Society Web site are made with this in mind.

If your pH is high, say in the 8.0+ range, it would be easier to get a pH test kit and learn how much vinegar you need to add to your water to get the pH down to 6.5. That would make the calcium and magnesium in your water more available, and make supplementation unnecessary.

[AnonYMouse]

I suspect I had calcium deficiency when new growths blackened. I gave mg/ca supplement and new growths are now healthy. Do I know for certain, no.

[bil]

Originally Posted by Dollythehun

I don't want RO because I don't want to run the pump that much.

Really? I wouldn't drink it, and the RO I use for the orchids doesn't amount to that much, so our pump isn't exactly overloaded by that.

What I like about the RO water is that I add a suitable balanced fertiliser, and I know it will be ok.

[Dollythehun]

I agree, Bil. Aging pump here. Should have caught the unusual January rain last night. Back to OP, do you have a cal mag you like?