Cymbidium leaves dying from infection

[rbarata]

As a side note, here's a few photos of some of my Cymbs just to make you feel more at ease.
Not really good looking, right?
They are always outside and they bloom heavily. Ugly leaves and Cymbs are always hand in hand.

[Girl_With_An_Orchid]

I wonder if he is spraying the tops or the bottoms of the leaves. The top has the waxy cuticle but if I remember high school biology right, the bottom of the leaf has all the stomata so the food could get in that way. Shadeflower, does this person have a blog/ YouTube/ social whatever where he talked about this? I’d be interested to hear his thoughts.

---------- Post added at 11:27 AM ---------- Previous post was at 11:24 AM ----------

Roberta, wow! Those leaves are something! And they look very much like mine so definitely reassuring. Thank you!

[Roberta]

Originally Posted by Girl_With_An_Orchid;973903
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Roberta, wow! Those leaves are something! And they look very much like mine so definitely reassuring. Thank you!

Actually, those Cym photos were from Rbarata, but I have plenty of leaves that look like those too. Cyms tolerate abuse nicely, tend toward ugly leaves, but bloom anyway. (Or maybe the abuse helps...)

[Girl_With_An_Orchid]

Oh your right. Rbarata, thanks for the pics! I feel much better about mine now. I’m really grateful in general for this thread and everyone who’s posted. I was kinda freaking out about losing mine.

[Roberta]

With regard to fertilizer on the leaves... some orchids have evolved to actually channel runoff toward the roots. I'm thinking of Cym canaliculatum (V-shaped leaves capture dew in addition to rain). Of course, rain includes rotting organic matter above the plants in the trees, so it would do the same with nutrients. Vandas (strap leaf and semi-terete) do that too... they don't have pseudobulbs, so need to grab every bit of nutrition falling on them. And many Epidendrums too. The nutrients end up on the roots where they get absorbed, no matter how the plant acquires them. If they get their nutrition from detritus, it is really, really dilute. A higher amount of fertilizer may even tend inhibit blooming in some cases, favoring vegetative growth. (Do you want lots of pretty leaves or do you want flowers???) The guy who does the foliar feeding is actually giving the plants a much reduced dose of fertilizer that actually gets into the plant. That may explain the better blooms.

[Shadeflower]

you won't lose them GwaO but from my understanding the symptoms shown on rbarata's cymbs are caused by a potassium deficiency.

Mine just started too actually and I've been feeding a bloom booster which has been helping the leaves stay greener.

I know it can be difficult to diagnose deficiencies, I've been studying them for months now and they can generally be categorised.

This I am most certain by now is a potassium deficiency, corrected by feeding a bloom booster in autumn otherwise these symptoms worsen over winter.

But that's just my theory. Either way will do fine like mentioned. Don't think of a bloom booster as something you need to get your cymb to bloom. Think of a blooom booster as something to use during blooming to keep leaves from turnnig yellow shortly after. At least that is how I see them from now on.

nitrogen will cause a general yellowing but it will be even, whereas potassium causes brown spots or necrosis to appear with uneven yelllowing (half the leaf green, half yellow starting at the tip)

[Roberta]

I haven't used a bloom booster ever... Actually, not all that much of anything. But in a sense I'm cheating... I live in one of the best climates in the world for growing Cyms. Put them on patio, squirt them with the hose when I think about it (OK, I water a lot), and they bloom their little heads off. So maybe special treatments make a difference under less-than-ideal conditions but I have not seen that they are particularly sensitive to anything. (Before I started using time-release fertilizer, I still got good growth and lots of flowers, the time-release just makes them look a little better)

[Girl_With_An_Orchid]

I am currently using a high nitrogen fertilizer because I read that that helps get bulbs bigger. Mine a notoriously small and I hadn’t been able to figure out why. It’s probably because of light and water. Maybe the extra nitrogen isn’t helping like I thought though.

How does time release fertilizer work? Is it something I build into the potting mix? If so I’m assuming I would repot more often to replenish?

---------- Post added at 01:54 PM ---------- Previous post was at 01:51 PM ----------

Shadeflower, it took me a minute to realize who GwaO was 😅. Should I try using a bloom booster instead of a regular 20-20-20 fertilizer?

[rbarata]

you won't lose them GwaO but from my understanding the symptoms shown on rbarata's cymbs are caused by a potassium deficiency.

Those are old leaves dying, I think.
I fertilize them full dose in every watering with Rain Mix so I don't think there's a K deficiency.

[Roberta]

High nitrogen will tend to suppress blooming. Remember... fertilizer is the LEAST important cultural factor. Get everything else right, and it improves things. But it won't compensate for less-than-desirable culture in other areas. Get watering, light, air movement, temperature correct then worry about the fine points of fertilizer. Fertilizer is "vitamins" not "food" ... the food, carbs, comes from photosynthesis.

Time-release fertilizer mostly works by temperature - when it is warmer, it releases more. Which is, of course, when the most growth is happening. Look up Nutricote or Osmocote or Dynamite. I just sprinkle a little on the top of the pots once a year in spring. Depending on the formula, it's good for 6 or 9 months.

---------- Post added at 11:21 AM ---------- Previous post was at 11:01 AM ----------

I have rescued lots of "legacy Cyms" that have been neglected for years in cases of elderly growers who could no longer care for their plants, nobody even noticing until the owners passed on and their kids needed to sell the property... getting water from sprinklers but nothing else. (That is when the leaders of local societies get a phone call) They survive, grow, and bloom.(Outdoor conditions here give the Cyms what they need except for water) They grow better once they are repotted and get a little fert, but years without care (as long as they get watered) doesn't set them back much. The lesson... worry less about fertilizer and more about giving them the basics (water, light, air movement, temperature variation)