yellowing leaves-Masdevallia Floribunda

[VickiC]

Hi,
I have recently noticed yellowing leaves on my Masdevallia Floribunda that lives in my Exo-Terra tank (pic attached). I have had it several months and it has seemed be healthy all the while....no discolored leaves....growing nicely with roots crawling over the sphag medium surface. About a week ago, I noticed a slight yellowing of one leaf. That same leaf color very soon progressed to a dark yellow-brown and shortly thereafter another leaf began to turn a slight bit yellow. The only change to it's growing conditions is fertilizer. About a month or so ago, I changed from MSU orchid fertilizer for pure water mixed with distilled water to MSU fertilizer for well water (19-4-3), mixed with tap (approx. 7-7.5 ph, I believe). My Masdevallia's other growing conditions are and have been: temp about 76-80 degrees, an approx. 80-95% humidity and roughly 10-12 hrs. of 850-1000 fc of artificial light. I have misted it daily and watered it every 5-6 days. I wondered if the fertilizer change is the problem, why would the leaf yellowing not appear for an approx. 3 wks.

I would appreciate your opinion and your advice.
Vicki

[L I Jane]

It could be the older leaves are dying off gradually.Happens on all of mine at one time or another but if it happens to all at one time--something is going on.

[quiltergal]

Vicki I think it's more likely it's not liking a change in the water. Masdies are notorious for being fussy about water quality. I water all of mine with distilled or RO only and I only fert maybe once a month.

[whygreenberg]

Yeah, Vicki...I concur with Terri. They are fussy about water and do not like much fertilizer. I use tap water (b/c we've got really amazing tap water in the NYC area) but also only fertilize about once a month.

[VickiC]

Thank you, I've never thought about this.
Vicki

Originally Posted by L I Jane

It could be the older leaves are dying off gradually.Happens on all of mine at one time or another but if it happens to all at one time--something is going on.

[VickiC]

Thank you, Terri and Yvan.

None of my other orchid-family members have complained about the water change, but I guess what people say is right: there's one in every bunch. lol

So, I'll buy a gallon of distilled water, just for Ms. Masdi. A gallon should last her quite a while.

After I posted my question to you, I took another look in my Exo Terra, and I noticed then that my Maxillaria variabilis 'Grace' has just a very tiny tinge on one of it's leaves, so I think I'm gonna share the gallon of distilled with her, too.

Let me know, please, if you advise differently.
Thanks again for your help,
Vicki