I have a ? about my NUN orchid

[CJR66204]

This is a first for me, to have anything wrong with this Orchid, I have had it a few years and never had anything wrong with it.. But I can see know on the new growth it has black lines I don't know if this is bad/or really bad.. and I don't know much about leafs of plants So the big ?... Is what is it? why did it happen? and how can I keep it from happing again?

Thanks to all who answers!

[WhiteRabbit]

I don't grow these, but hopefully that isn't serious - it doesn't look too bad

Hopefully some other members can chime in!

[CJR66204]

Ya I just didn't want to cut it off, but thanks for the input

[King_of_orchid_growing:)]

Probably the first signs of a calcium or magnesium deficiency. From what I understand Phaius tankervilleae grows as a terrestrial in places with a lot of limestone hills. China is chock full of limestone, as are places such as Taiwan, and Malaysia.

In other words, the organic debris is covering limestone.

When it rains, the orchid is receiving a rather good dosage of Ca and Mg.

Try adding some dolomite.

I don't know how you are with fertilizing your Phaius tankervilleae, but I'll mention this anyways...

If you haven't been diligent with your fertilizing regimen, I suggest being more on top of it.

[CJR66204]

I fertilize ever other watering with MG Orchid Fertilizer. It seems to work with all my other Orchids, Or do you have names of any other good Orchid fertilize that I can use?..

Thanks again

King_Of_Orchid_Growing

[King_of_orchid_growing:)]

I'm assuming the "MG" you're referring to is "Miracle-Gro"; so that would mean you're using "Miracle-Gro Water Soluble Orchid Food". Am I correct?

First and foremost, I checked an ad for this product to see what the N(nitrogen) - P (phosphorous) - K (potassium) ratio is. According to the ad, the N-P-K ratio is 30-10-10. Am I correct?

If so, the amount of K (potassium) is lacking. It should be just as high, ratio-wise, as N (nitrogen), or very close to it. So, something like 30-10-30 or 30-10-25, for example, are far more acceptable than 30-10-10.

Also, I don't know what kind of nitrogen source the Miracle-Gro Water Soluble Orchid Food utilizes. There are 3 sources of nitrogen that fertilizers normally contain:

1. Ammonium nitrogen - an ammonium based source of nitrogen.

2. Nitrate nitrogen - as the name suggests, a nitrate based source of nitrogen.

3. Urea - a nitrogen source based on what constitutes urea.

Here's a video and you'll get an idea of how the nitrogen cycle works:

Nitrogen cycle in the soil - YouTube

Also, if I'm not mistaken, Ca (the chemical elemental symbol for calcium) and Mg (the chemical elemental symbol for magnesium), is not included in the list of nutrients in the Miracle-Gro Water Soluble Orchid Food.

Like I said, add dolomite. Dolomite will leach calcium and magnesium over time. You can find dolomite in places like Armstrong or any other local nursery.

Also, you may want to consider a fertilizer that doesn't use urea as a source of nitrogen. I'm not sure if the Miracle-Gro Water Soluble Orchid Food uses urea or not, but you may want to utilize a fertilizer that utilizes either ammonium or nitrate as a nitrogen source.

[Myrle Diefendorf]

I have Phaius Tankerville, and have had for several years. They are used as landscape plants in Florida. Mine are potted in huge pots, and have to be divided every so often. I use part bark and part potting soil, and place them outside from March til November, when I put them in an unheated garage with a bright window and let them have a slightly drier colder winter rest. They are always sending up huge bloom stalks by February. I use regular orchid fertilizer with all the trace elements.

[Myrle Diefendorf]

PS. I live in So Carolina, zone 7b or 8a depending on global warming.

[King_of_orchid_growing:)]

There is evidence that suggests that certain parts of Florida will contain limestone:

Florida Soils - University of Florida's Gardening in a Minute

Limestone contains Ca and Mg.

[Myrle Diefendorf]

Yes, and I have been told that as fir bark decomposes it takes lime from the media and therefore it is wise to add a bit of pelleted limestone to pots every so often.