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Black Rot On Orchids: What it is, How it Gets There, and How to Treat It
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Oct 3, 2024
Black spots that start small but soon take over an entire leaf are common orchid problems called Black Rot. If not controlled soon, Black Rot will travel form the leaf down toward the crown, killing the pseudobulb, rhizome, and roots. This fungus, along with others in its family like Pythium ultimum which also cause Black Rot, is extremely fast-spreading. If not treated, within two weeks your orchid could be dead.If you want the full explanation of this video in writing, go to https://orchideria.com/orchid-black-rot/ On Orchideria.com, you can find more in-depth guides and all the access to our information, tutorials, guides, and much more... all for free! Happy Cultivating! ______________________ TIME STAMPS: HASHTAGS: #orchidcare #orchid #Orchideria #AmandaMatthews _______________________ SOCIAL MEDIA: Website: https://orchideria.com Facebook: https://www.facebook.com/orchideria.orchid.terrariums Instagram (Orchideria): https://www.instagram.com/orchideria.orchid.terrariums/ Instagram (Amanda Matthews - personal): https://www.instagram.com/amanda_june_matthews/ Pinterest: https://www.pinterest.com/Orchideria/ ________________
View Video Transcript
0:00
What is black rot, how it gets there, how to treat it, and how to keep your orchids safe from it in the future
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Hi, I'm Amanda Matthews and thank you for watching this video at Orcadaria, where I share my tips of how to grow orchids indoors
0:19
since my outside climate just isn't that great for orchid care. Now black rot starts on the leaf, but it quickly spreads to the stem of the orchid
0:30
that's where it's going to kill the stem or if you have a sympodial orchid like a catelia or dendrobium
0:37
it will kill the pseudobob or the canes of the orchid. It acts very quickly if you do not treat this in two weeks
0:45
your orchid could be dead. Now there's not just one fungus that causes black rot. There are several
0:52
but the main one is pythium ultimum. Let's take a look at why this black rot
0:59
comes to our orchids in the first place. Well, black rot loves to be in a climate that is very
1:05
similar to orchids, which is 75 to 86 degrees Fahrenheit and relative humidity close to 80%. So if you are
1:16
doing your orchid care properly, you have a humidifier, you are misting the environment, you are
1:22
keeping that humidity high in your home, black rot could be a reward for all that. Now, black rock
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ROT does not only affect orchids. It also affects corn plantations, apple orchards, and strawberry
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patches. And all of these have one thing in common. They have very high water requirement
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Notice the problem here is water. And that's where we get into the problem with the black rot
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That's why it comes because either you are watering improperly or poorly. How do I know if it's black rot or black
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spots. Well, black rot will start as a yellowing of the very end of the tip of the orchid
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and this yellowing will progress and soon turn black. There might be a black spot here and there
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but when the black sets in, it's going to cover like a kindergarten
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or got its fingers and just smudge the entire leaf. So you're going to have a covering of just
2:25
you know, the entire leaf of black. Another thing that's, might confuse you that might not be exactly black. It might be a purplish black color. In time
2:38
this leaf will crumble, wilt, and fall off. And it spreads so fast. If you have a phalanopsis
2:47
orchid, it's not affected that much. The two main orchids that are affected are cattlia and
2:53
endrobium orchids. And why this happens, I'm not so sure, but they are. Each orchid has their
2:59
kryptonite, I guess. But that doesn't mean that your orchid is, oh, I've got a phallinopsis
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I'm home free, because others that come in like second place of black rock are epidemdrum, vanda
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pathopetalum and laelocatlia Those also have a high incidence of black rot and you notice these orchids also like to have water lots of water you notice this is a reoccurring thing here i trying
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to make you catch on how does it spread like if i have one orchid how do i know it's not going to spread
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to the others black rot spreads through water droplets so if i'm misting this orchid like that
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which is totally wrong and I just leave it here and I leave it in a corner of my house that has
3:48
no air circulation that water's just going to sit on the leaf it's going to sit in the suitable
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and it's going to take hours and hours to evaporate that is what is going to cause black rot
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and how does it transfer from one orchid to the other well if you have a huge pot and you're
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dunking one orchid in and then get another orchid and dunk it in
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that's also going to spread that black rot from one orchid to the other
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If you happen to touch the nozzle of your mister on this orchid with black rot
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and then touch the other, that black rot will spread to the others because, again, water
4:30
The other way it spreads is also through gardening tools, just as the black spot wood black rot also does too
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I just want to say a heads up. I can mist my orchids like this because
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I always keep my overhead fan on and this is going to be evaporated quicker than it should be
4:48
and my environment is extremely dry so I don't really have that problem. The third way that
4:54
black rot spreads is through potting material that you have not sterilized. For example, I'm going
5:01
to repot this orchid and I use a different pot and I don't clean that pot out. So I get an orchid
5:07
that has black rod. I give up on it. I throw it out. I keep the pot because the orchid
5:12
pots are quite expensive. Then I reuse it without properly sterilizing it or without
5:18
properly cleaning it to get rid of this black rot. That can stay in the orchid pot and transfer like that
5:25
So when you do repot, always make sure that you clean your orchid pot out before, you know
5:31
changing orchids in different pots. Before I go on to the next point, if this video is providing
5:37
any helpful information, please give it a like or comment below. So
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I know what works. It's just good feedback for me because I still am a kind of new channel. I haven't been on
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that long. So I'm still learning at this whole YouTube thing and it really helps me to get some
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kind of idea. The third way that black rot spreads is through proximity. So if this leaf is
6:01
actually touching another orchids leaf, it can travel through the airdroppist and through the spores
6:09
on the fungus. If you are watering properly, and you are keeping a high evaporation rate with high air circulation and you are mist
6:19
There's nothing wrong with misting like this. I have seen people say that, oh, you can't get water
6:24
in the crown because you're going to get crown rock. And that's not true. And I'll tell you why
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When you always look back to nature see how nature does it Well in the rainforest this orchid going to be on a tree It going to be higher up and it going to get rained on And rain not going to be picky and say
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I'm not going to rain on the crown. I'm just going to rain on the underside of the leaf
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Well, that doesn't happen. When it rains, it really downpours. And this whole orchid's going to get
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drenched. So the water that gets in the crown, that's not going to cause the crown
7:00
rot. I know we're talking about black rot, but it's the same principle here. It's not going to cause
7:05
crown rot or black rot. What is going to cause it is if that water doesn't evaporate quickly
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So let's think about how this can translate into your home office or your home environment or
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your living room or your bathroom or wherever you have your orchid. Number one, check your
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humidifier. If your humidifier has some kind of fungus already in it and it's just blow
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out all these water droplets all over your orchids, you're spreading the black rot all over them
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Second, if you are misting, how quickly does that mist evaporate from your environment
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Because you can already see here, my leaf is already starting to dry up
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I mean, and number three, is your humidity too high? Sometimes we think, oh yeah, I really like orchids
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I'm going to put them in the bathroom or I'm going to put them in the kitchen. and even though those humidities can get extremely high, how long do they stay high
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So check these things out to see how your black rod is spreading from one orchid to the next
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If you do have a high humidity environment and you still want to mist, that is actually fine
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but then just take a paper towel and dry off the parts of the orchid where it did get water
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Now black rot will not only stay on the leaf, it will travel too
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to the stem of the orchid and then travel to the roots of the orchid
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which is what we call root rot. We usually associate root rot with only overwatering
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or having a potting media that is too compact and it won't let that potting media dry out
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or you have an orchid pot that doesn't have holes, doesn't provide air circulation
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but this is the second way that black rock can get to the roots and cause root rot
8:57
As soon as you see, a huge black patch. Cut that leaf off and we'll get into treatments in a second. But what happens
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to the potting medium? I'm talking about the black rot that moves to the roots, which is now
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denominated root rot. Number one is going to change the pH of your potting media. So if your pH was
9:16
already great, which is between 5.5 and 6.5 of most orchids, it's going to drop that. It's going
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to become extremely acidic, which also accelerates fungal growth. So you see how it's like a cycle
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Once it gets into this cycle, just one item feeds on another. Number two, it traps in water
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So this fungus is not going to let that water exit the pot quickly. It's going to retain more water
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and more water provides more fungus So number three it makes gas change almost impossible And number four it doesn let the roots photosynthesize because it breaks down that chlorophyll in the roots So even though your potting media is full of water your roots will
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not absorb that water and transfer it all the way through your orchid. The best part of this
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video, how to treat this black rot. The first thing you want to do is you want to cut off any
10:11
portion of the black rot. And do not, like if the black rod is from here to here, you're not going to
10:17
cut here. You're going to cut down here to make sure there is no black rot left in this orchid
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Treat the wound where you cut it. You can use cinnamon. You can use fungicide. You can use
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wax. I've seen people use wax. You can use anything to really seal that open wound off so that
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more fungus came in there in the first place. So there's probably more fungus spores in the
10:43
air. You need to seal that off. Number three, when you repot add charcoal
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Charcoal is an amazing potting media because it does absorb some of these fungus
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How this happens is that charcoal will deplete the minerals that both fungus and bacteria need
11:00
to reproduce. So they are an excellent addition to your potting media
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It doesn't kill the bacteria or the fungus, but it does slow down the propagation
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So your orchid does have a chance of surviving when there's more charcoal in your potting media
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The last part is that you do need to treat your entire orchid with a fungicide, not a bacteriocyte, but a fungicide
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And this is where fiza-20 really doesn't cut it, but there are two that you can try out
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One is called captain. The other is called Alliette. Of course, I don't sponsor these products, but the best thing you can do is to go to growers in your region
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because everyone is from a different part of the world, has a different growing conditions
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Go to people who grow strawberries, apples, and corn, and see how they treat the black rot
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That is your best form of treating orchids in your area to get information from the local growers and see how they do it
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If you are not sure that you have black rot, you can go to the playlist on my channel
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And there is a section called orchid problems. And in orchid problems, I talk about mineral deficiency, I talk about the black spot, talk about how to identify
12:16
what kind of problem is going on with your orchids. So take a look at that playlist
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And the final tip, you need to remove this orchid from your collection. Do not keep it close to the
12:28
other orchids because it does spread. It is airborne if they're in close proximity, but it does
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travel on water droplets. And so it's just too easy to spread from one orchid to the other. So
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remove it from your collection after you've given it a good treatment. I want to suggest two videos
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so that you can continue your orchid care learning. And one is the black spots video
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And the other is how to identify what's wrong with your orchid. The steps I go through like, oh no, what's this
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And okay, how do I eliminate which one is which? I've hoped you enjoyed this video
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If you have, give it again, give it a great like. That really helps me, honestly
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just so I know what kind of videos to make for you guys in the future. And I wish you the best in your orchid care
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Happy cultivating
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