New growth on cattleya is black...what's going on?

[boisemomma]

My Pot.Eye Candy is getting new growth but some of the new growth is totally black..my other cattleya's are not doing this..I do spray with a fungicide monthly..hope someone can help me figure this out..see pictures..

[HighSeas]

I had that problem with a couple Catts and because I also use a systemic, couldn't imagine any kind of fungal issue. So I did a little research and discovered (By Sue Bottom actually) that this is a primary symptom seen with Calcium deficiency. I sprinkled some gypsum over the media and haven't had the problem since.

[Nexogen]

Images of Calcium Deficiency on Orchids

[silken]

Originally Posted by Nexogen

Images of Calcium Deficiency on Orchids

My Toshie Aoki new growths die off as pictured in one of these symptoms. But I started adding calcium and mag. a year ago to my orchids. Does it take a long time to have a positive impact? Or maybe I don't use enough. Our water has enough minerals in it that there should be some in it too.

[RHF]

What is the conductivity of the groundwater in Boise? If it is hard, a little well water (unsoftened) would give you all the calcium you need.

I would watch it for any progression toward the rhizome - just in case it is a black rot fungus - if it is, amputate to save the plant.

[Nexogen]

Originally Posted by silken

My Toshie Aoki new growths die off as pictured in one of these symptoms. But I started adding calcium and mag. a year ago to my orchids. Does it take a long time to have a positive impact? Or maybe I don't use enough. Our water has enough minerals in it that there should be some in it too.

Calcium is deposited in plants cell walls during their formation, once incorporated into plant tissue is immobile so a constant supply is necessary for continued growth.
Calcium deficiency can be caused by; too much potassium, over fertilizing, the nutrients can be there but the roots can’t take them in, to make sure your plant is getting what it needs, keep media pH to 5.2 and 6.5.
Higher EC levels in the nutrient solution reduce the uptake of calcium, unlike nitrogen and potassium which increase in concentration in leaf tissue with higher EC levels. Reducing the EC of the nutrient enhances water uptake and with this, more calcium can be taken up and transported within the plant to developing tissue.

[tucker85]

It looks like Black Rot. Cut all the affected tissue off below all the black and with a margin of green. Give the plant plenty of calcium when it's putting on new growth.

[silken]

Originally Posted by Nexogen

Calcium is deposited in plants cell walls during their formation, once incorporated into plant tissue is immobile so a constant supply is necessary for continued growth.
Calcium deficiency can be caused by; too much potassium, over fertilizing, the nutrients can be there but the roots can’t take them in, to make sure your plant is getting what it needs, keep media pH to 5.2 and 6.5.
Higher EC levels in the nutrient solution reduce the uptake of calcium, unlike nitrogen and potassium which increase in concentration in leaf tissue with higher EC levels. Reducing the EC of the nutrient enhances water uptake and with this, more calcium can be taken up and transported within the plant to developing tissue.

Thanks for the explanation. We do have high pH for our tap water-around 8.5 or 9 and I have just recently bought some pH down treatment and some more Cal-mag supplement. I have used rain water in the past but have a problem keeping it from turning green. So I prefer the tap water which may be causing my problem of black spots and new growths dying off in some Cattleyas.

[boisemomma]

Thanks for all the replies..I did go out and buy some gypsum..is it possible to overdose with calcium? should I treat all my orchids or only those who show a problem?

[Leafmite]

I don't think orchids need great amounts but a steady supply is important. I add eggshells to my orchids and then powdered milk to the water. I started this a few years ago after I lost many orchids to Calcium deficiency (after I no longer had a goldfish pond that supplied me with water for my plants) and I haven't had any problems since. Good luck!