Brassavola seedling leaves got blackish lines along midrib

[sweta]

Thank you for the response. This seedling came in sphag moss so I thought of not changing the media drastically since its a seedling..so I added some bark but has more of sphagnum moss. After seeing your post I removed the sphagnum moss. I find it a challenge to keep up with watering in dry home temperatures. You are right that the roots have been in wet soggy sphagnum moss. In addition the warmth from the grow lights might have cause some kind of infection. Can I use physan instead of copper fungicide. Btw I use rain water with repotme fertilizer.

[sweta]

Originally Posted by sweta

Thank you for the response. This seedling came in sphag moss so I thought of not changing the media drastically since its a seedling..so I added some bark but has more of sphagnum moss. After seeing your post I removed the sphagnum moss. I find it a challenge to keep up with watering in dry home temperatures. You are right that the roots have been in wet soggy sphagnum moss. In addition the warmth from the grow lights might have cause some kind of infection. Can I use physan instead of copper fungicide. Btw I use rain water with repotme fertilizer.

Here is another picture. The bottom part of leaf is turning dark.

[MateoinLosAngeles]

Originally Posted by sweta

In addition the warmth from the grow lights might have cause some kind of infection. Can I use physan instead of copper fungicide. Btw I use rain water with repotme fertilizer.

Idk what kind of grow lights you use but the LEDs I use don't really increase the temperature and are generally safe to use. It's hard to tell if you're experiencing rot by the photo, but that'd be most likely be due to staying in a wet and soggy medium with insufficient drainage or aeration.

The instructions for mixing on repotme fertilizers leads to 200ppm N, which is fine if you do biweekly. I'd use half strength or less weekly. Btw the Repotme fertilizer is the MSU fertilizer which can be obtained at much cheaper prices at Kelley's Korner, I use K-lite from FirstRays.com

I use both Physan 20 and Liquid Copper Fertilizer. I drench the entire plant and medium in Physan 20, if I have root rot I may let medium soak in Physan for a couple of minutes. Then I spray Liquid Copper Fungicide on leaves. I've never had a problem but I also will say that I haven't done this with my Brassavolas (I've done it with Cattleyas however). I got my Brassavola as a seedling and it had very vigorous growth potted in an airy basket with fine bark (And some leca and sphag), so I've only used Quantum and Kelpak on it, but not fungicides or pesticides.

If that is rot then you need to cut the pseudobulb, apply cinammon, use Physan 20, etc., etc. classic rot instructions you can find anywhere. But make sure it's rot first. As I said it looks fine to me, probably the roots will appreciate being in an aery medium and aery pot.

[sweta]

It doesnt look like rot. I'm very careful when watering and dont allow water to get into leaf joins. I use this growing light

Amazon.com

Roots look very healthy. I'm suspecting due to sphagnum moss being wet all the time must have caused too much of humidity. It was doing well on the window sill only after moving it away and putting it under grow lights I'm seeing this.

Thanks for information on alternative to repotme MSU fertilizer. Its actually very expensive in repotme. So glad to know other options.

[MateoinLosAngeles]

Originally Posted by sweta

Amazon.com
.

I highly doubt those lights are too hot since a Brassavola is an intermediate to hot grower, unless they're literally touching the leaves, but you can place them pretty close.

As Estación said, this plant can show purple/dark dots on the tips if it's getting enough light, not really in the creases but if it's not spreading, it could really be anything. A virus can't be ruled out, for example. But I do think that plant looks okay, it just might be a bit sluggish due to conditions not being optimal.

Think of day temperatures of 75-80ºF and 65ºF-70ºF at night. It'll be happier towards the warmer end of the spectrum.

It doesn't need super high humidity but it does need something closer to 40-50%. 30% is too low.

Keeping soppy Sphagnum plus cold temperatures will equal the sluggish growth you're seeing. Is the pot too big? The bigger it is, the wetter it will stay.

Regarding fungicides, I personally use them as preventative, especially with new plants. In this forum people are not very keen to that idea, however, you will see literature that recommends fungicides as preventative as opposed to treatments. Many growers use them monthly or at least twice a year (Seasonally). Norman Fang talks about drenching many of his plants in Physan 20 monthly.

I only do it with newer plants both to protect my collection and to give the newer plant a shot at being protected while it adapts to the new environment. Then as they get established in my environment I start a routine of watering with Quantum Total, over time the beneficial bacteria in Quantum will outcompete pathogens so fungicides really become unnecessary. Besides, they would kill the beneficial bacteria as well.

In your case I would look into finding a way to keep this plant airy (net pots, bark medium, air circulation), well lit (grow lights, windowsill), more humid and warm (perhaps a heat mat or a mini greenhouse).

So TL;DR: the plant is too cold.