Important!! Calcium Deficiency
 

All,

Over the past 2-3 years, I've had to re-learn how to grow my orchids indoors for either all or part of the year. The plants inside get RO water, so long story short, I've come to realize that many of my 'chids have been suffering from calcium deficiency. I've been adding Ca/Mg to my watering regime since I got to Texas, but it was not enough. In the past month or so, I've taken steps to increase my Ca dosage, but I won't see results until the end of the next growing season in many of my plants. :((

Its a VERY avoidable problem that masks itself as rot on new growths. Here is a link to pictures of Ca deficiency in orchids:
Images of Calcium Deficiency on Orchids

Here is a great written description of Ca deficiency in orchids, including how to fix the problem and why it happens: http://rockhamptonorchidsociety.com....Deficiency.pdf

I figured this is something that everyone on OB should read!!

I agree with you 100% but, the problem for orchids is that they are unable to adequately limit their calcium uptake, and will absorb too much of it when available, resulting in cellular pH too high. Some orchids also have difficulties absorbing Fe, Mn, Cu, or Zn, which is more tightly held in alkaline media, another reason why they thrive in low pH media.

Can you describe the effects of cellular pH being too high, due to excessive calcium?

For the most part, epiphytic orchids get the majority of their nutrients from the solutions applied (rainfall cascading through the forest canopy in the wild), and not from the substrate.

Nexogen, where did you get this information that orchids can take up too much calcium? I haven't read that before.

Some topics have a tendency to go round and round with no end in sight..... In the end, noone ever agrees. Just an observation.

:badh:

Steve, I have been pretty happy using gypsum and Epsom salts (Ca and Mg sulfates, dissolved 1 tsp/gal). These provide sulfur also. I use this as a stock solution, add several ounces to a gallon of water when I water.

There are other formulations that are fine for providing Ca and Mg, but mine seems to help ward off diseases and is fairly inexpensive.

Calcium deficiency has been a subject of discussion here many times. The importance of additional Ca-support cannot be commented too often. Thanks for the useful links, which also include illustrative pictures.
Rainwater does not contain Calcium. To my knowledge in nature the binding and allocation of calcium is accomplished by complex biological crusts.

Thanks for the PSA, Steve. I've started seeing these symptoms on some of my potted catts, since I've reduced fertilizers to about 20 ppm N. The problem is, the Ca and Mg in those fertilizers are formulated for dosages of 100+ ppm N, so obviously I need to supplement.

A question for those who use the same watering can or sprayer for all their orchids - how do you deal with phrags, which wouldn't appreciate heavy supplementation?

I don't buy that, Alla.

Fertilizer formulations are designed to provide the nutrients as specific ratios to the nitrogen, so no matter what the concentration, the ratio remains constant.

If you lower the concentration, you need to increase the frequency of application, so that the proper mass of nutrients are applied per unit time.

I feed at about 35 ppm N, and am not experiencing any signs of deficiency. I feed about every 2-3 days, depending upon the amount of sunlight and temperature.

I'm also curious about a source for this info since I've heard that its pretty tough for orchids to OD on Ca/Mg. If I remember correctly, I believe Alan Koch at Gold Country Orchids says in his lecture that lots of Ca/Mg is really good for epiphytic orchids.

Yes, I figured if someone who has been growing orchids for a loooooong time like myself overlooks such a simple task as Calcium supplementation, then there are probably many more that do as well.

I know Phrags don't like too much fertilizer, but I wonder if Ca is the same?

When the plant is weak and roots are bad, the cure can be very recalcitrant. Here is a new soft yellowish leaf oc C. skinneri with tip dieback caused by Ca-deficiency. The other leaf of this bifoliate species is already lost, and both leaves of last years bulb as well.
The other plant is C. labiata. Roots are bad, with nearly no new root growth. Last years bulb lost its leaf quickly. This years bulb is stunted.

Excellent pics! They definitely help people ID this problem and you're right about the cure being difficult. Simply reversing Ca deficiency can't cure the growths that have suffered from it and the plant can suffer immensly as the new growths and roots are stunted or just don't grow.

This is a great post! I hope everyone reads it.
I learned about calcium deficiency the hard way. I had always used my pond water (the fertilizer for lotus and lilies is high in calcium) to water my plants during the summer and when I gave up having a pond, I began to use rain water. I didn't realize that my orchid fertilizer wasn't complete as most of the fertilizers I used for my other plants. I lost quite a few of my cattleyas and a couple of other orchids to 'Black Rot'. Yes, I felt stupid when I realized what had happened (I grow many other plants) and began right away adding calcium. I haven't had a problem since. Now, I try to warn others so they don't go through the same trauma.

I'm trying to rescue some catts that I thought had been underwatered, but are actually showing all the symptoms of Ca deficiency. They're now mounted on a cement composite wall, so they're getting plenty of Ca, and new growths are coming in nice and green. They're still stunted, though, so it will be a long road to recovery.

I'm loving this thread. I went right out and got my gypsum out of the shed had Epsom salts in the basement. So I mixed some up my gypsum is pelleted so it took allot of shaking to get most of it mixed up.

Question is gypsum better than dolomite lime as I have them both. I use them on my yard and garden. I have read on here about the lime as well and have put it in my phrag and paph just the pellets.

Dolomite lime will make epsom salts unnecessary. It has cal and mag in the right proportion.

Gypsum & Epsom salts are both readily soluble, whereas the dolomitic lime (limestone) is slowly soluble. Also, G&E will not change pH (at least not by much), whereas the DL will increase pH. Part of the reason that DL is applied to lawns & gardens is to modify pH.

This is true! However, Roy Tokunaga at H&R was telling me that he sprinkles dolomite on top of orchids potted in spag to keep the pH at the correct level. If you've ever seen spag with a slimy film growing on top, its a sign the pH has gotten too low. Dolomite will prevent this. I think for plants potted in spag, sprinkling the surface of the media is the simplest way get the correct amount of Ca/Mg to the orchids.

A dissolvable application of Ca/Mg is probably better suited for all other media, though I'm sure there are people doing just the opposite with good results.

I use Botanicare CAL-MAG Plus, but I also periodically use a pinch of Epsom Salts in my mix to supply a little sulphur, which is lacking in my local water supply. J. R. Peters Lab states that my water has about 9 ppm sulphur and 10-80 ppm is normal range.

One caveat they give about adding Epsom Salts for sulphur: "DO NOT MIX any sulfur-containing compounds with calcium, an insoluble precipitate will form." I don't think that's a problem as long as I add the Epsom Salts to the diluted mix; in other words, don't combine it with undiluted Cal-Mag or you will lock up the calcium in a precipitate.

Thanks for posting! The pictures are really helpful. I think a few of my orchids need some calcium.

I've seen this warning regarding using calcium nitrate with any kind of sulfate; at least one brand of Cal-Mag (Brandt) seems to contain soluble calcium and nitrate-nitrogen, though there could be different Cal-Mag formulations. My recollection (which could be a bit fuzzy, and you should verify) is that the precipitate is gypsum (calcium sulfate), which will eventually dissolve again; J.R. Peters may be able to confirm. I think you are probably right about dilute mixes not being a problem.

Ok then I will use the gypsum with Epsom salts. Would you put it in with your regular fert or feed alone? I fed mine alone and need to do the rest. I do not have a scientific mind so much of what you guy's say's goes over my head.

Trying, trying. I am thinking some of mine might need this as well. I have been using rain water all summer and still am but have started to add a little bit of my well water to it.

I've used the gypsum-Epsom solution (1 tsp each/gal), added a few ounces of this solution either with or without fertilizer per gallon of water. I'm not really scientific about the amount, but my plants outdoors last summer (which was incredibly wet) showed no signs of bacterial or fungal problems. Either the gypsum-Epsom was working, or I got really, really lucky.

I have some vandaceous plants in vase culture that get a small amount of the Ca+Mg and a small pinch of fertilizer with nearly every watering. Other plants growing with roots in medium get Ca+Mg a few times a month, with or without dilute fertilizer.

Thanks I just watered the rest of what I think I didn't water last time with it. I used it just itself.