Orchid Root Rot: Causes, Symptoms & Cure

Every orchid owner who’s kept orchids for a while will have faced rot. Rot can affect leaves, roots, and even the crown. But what causes root rot, what symptoms might you spot if it occurs, and most importantly… How do you fix it?

Why are my orchid’s roots rotten? Two factors cause root rot: the presence of water, and the presence of bacteria or fungus that eat away at roots. If orchid roots are never allowed to dry out, the bacteria and water act continually on the root to rot it. The roots first turn white from overwatering, then brown or black from rot, at which point they will turn soft and soggy too. You may also notice the unique smell of rot. How do you fix root rot in orchids? First, de-pot your plant and cut away any rotten roots. Wash out the inside of your orchid’s pot and replace the potting mix with new, suitable mix like coconut bark.

The guide below looks at exactly what causes root rot in orchids, and what rotten orchid roots looks like. We’ll also cover how to trim orchid roots safely, without cutting away healthy ones, and without causing knock-on infections and rot from doing it wrong!

What Causes Root Rot in Orchids?

There are two things that cause rot in orchid roots. These are water and pathogens (bacteria or fungus). When these two things combine in a particular way, rot is sure to result.

Water, Especially Standing Water

Rot is impossible without the presence of water.

Water serves several purposes in enabling rot. First, bacteria and fungus need water to survive: they absorb it, use it to grow, and use it to reproduce. Like animals and plants, bacteria are mostly water, so when they make copies of themselves—which is how more bacteria are made—they need lots of water available. So in a very basic sense, bacteria rely on water to exist. Fungus relies on water in a similar way.

Water also allows the bacteria or fungus that create rot to spread. These can’t move quickly across surfaces on their own. Water allows them much greater freedom. Another way that water causes rot is that it helps break down plant tissue. In the continual presence of water, orchid roots grow larger and softer. This allows the fungus or bacteria easier access to the root, and hastens the speed at which it breaks down.

Orchid Root Fungus & Bacteria

Water isn’t sufficient to cause rot, though. You need bacteria or fungus to start an infection, which can then gradually grow and get worse. It will then look like recognizable rot.

Bacteria, in particular, are found everywhere. They’re in the air, they’re on every surface in your home, and they’re in your orchid’s pot. But they normally stay at manageable levels. What makes bacterial infections get out of control is when they have the precursors they need to reproduce: water and some kind of food. In your orchid’s pot, with standing water, they have both of these things (the roots being their ‘food’). Fungus can also cause rot in the same way.

There is no way to fully get rid of bacteria or fungi. You can make surfaces sterile, but they don’t then stay sterile indefinitely. This means that there will always be pathogens that could rot your orchid’s leaves in its pot. But if you follow a suitable watering schedule, and allow the potting mix/roots to dry out between waterings, they won’t get out of control and cause rot.

What Do Rotten Orchid Roots Look Like? (Symptoms)

The symptoms of root rot are easy to see. If your orchid has a see-through inner pot, all you have to do is lift it from the outer pot and look at its roots. Some of these symptoms can be spotted early on, while others are a sign of later-stage root rot.

Wet Roots & Standing Water

Your orchid shouldn’t sit permanently in standing water. Ideally, you want to bathe it for fifteen minutes, then allow it to almost fully drain before putting it back in its outer pot. By the time you water it next, the medium and the roots inside the pot should be dry (bar a few droplets of condensation).

What you don’t want to see is lots of standing water. If you bathe your orchid for fifteen minutes, but don’t allow it to drain before putting it back in its outer pot, lots of water will collect at the bottom. Depending on the construction of the pots you use, your orchid’s roots may be in contact with this water. If there’s only a little, it may be absorbed; but if there’s a lot, it can stay there for longer than a week.

This is a big problem if you don’t pay attention to it. The next time you water your orchids, take the inner pot from the outer pot and check if there’s any standing water in there. If there is, you might want to change your watering method, or the frequency with which you water your orchids.

This is the earliest sign you can spot. If you correct the problem at this point, true root rot may never develop.

Soggy, Soft Roots

If your orchid’s roots are forced to sit in water, they become swollen and discolored. That’s because they absorb as much water as they can possibly handle.

At first, the root will be firm. Orchid roots should always have a firm crispness to them. They should spring back into place when bent, and should have a texture that feels like it would snap if you bent it too far (although, of course, you shouldn’t do that).

But as rot takes hold, the roots will become soft and soggy. Rot breaks down the structure of the root, making it lose its firmness and shape. You may notice that at the point where the rot began, the root can fold or bend in any direction, almost like a soggy mass of card or paper. This will only continue to get worse if you don’t deal with the problem; the rotten section of root is already damaged beyond repair.

Discolored Orchid Roots

Rot, overwatering and standing water cause the roots to change color.

A healthy orchid root is a silvery-gray color. When it absorbs water, it turns green. The color of healthy roots can vary from vivid green to deep green.

What you don’t want to see are pure white, or light yellow roots. This is an indication that the roots have been overwatered. There is an obvious correlation between overwatering and root rot: overwatering means that the roots are never allowed to fully dry, which is what makes rot possible.

If the root is allowed to rot for a long time, it will change color yet again. Rather than green, or even white, fully rotted orchid roots become dark brown or black. And why do orchid roots turn black when they rot? It’s a result of the bacteria or fungus breaking the root down and, essentially, eating it. White roots are still functional, so if you stop overwatering, they and your plant will be fine. But black, rotten roots can’t be recovered.

Smelly Rotten Orchid Roots

Another symptom of rot is the smell. The smell of orchid roots rotting is similar to that of other things rotting. It’s difficult to describe, but you’ll know when you smell it!

Again, this is a result of the bacteria or fungus breaking down the roots and consuming them. The smell is a combination of the gases the bacteria give off, and the broken-down tissue of the orchid root.

Can You Save an Orchid with Root Rot? (Cure)

You most definitely can save an orchid with root rot. Orchids are much more resilient than their reputation gives them credit for. Follow the steps below and there’s a good chance your orchid will survive.

1) What Do I Do If My Orchid Has Root Rot…? Stop Overwatering!

There’s no use cutting away any rotten roots if you don’t fix what’s causing them. You must immediately stop overwatering your orchids and leaving them in standing water.

One way to stop standing water is to leave your orchid out of its outer pot for a while, in only its inner pot. This will hasten evaporation from the potting mix, which is good. Your orchid’s roots have already absorbed the water they need. They may absorb some of the ‘leftovers’ between now and the next watering, but they don’t really need to.

While it’s drying, place the orchid on gravel on a plate. This will stop water from pooling underneath it, allowing it to drain fully. You can then place it back in its outer pot.

2) Should You Remove Rotten Orchid Roots?

Rotten roots can’t be recovered. There’s no method or hack to bring them back to life. All you can do is cut them away before they affect the healthy roots that are left.

The question, then, is how to remove rotten orchid roots. First, you’ll have to take your orchid from its pot. Get rid of all the potting mix in and around the roots. You can then take a proper look at all of your orchid’s roots to see which ones are rotten and which ones aren’t.

Begin by cutting away any obviously rotten parts using a sterile tool—put them in the bin. You should then try to untangle your orchid’s roots as best you can, as it’s often the roots at the center of the root ball which are rotten. That’s because the water that gets caught up there takes even longer to be absorbed or evaporated. If your orchid has a large root system, doing this can take quite a while.

When you cut away a rotten root, cut away a small part of health root above it too. This will ensure that absolutely no rot is remaining. Use both the way the root looks and the way that it feels under your fingers to judge whether it’s rotten or not.

3) Orchid Root Rot Hydrogen Peroxide

Hydrogen peroxide is a kind of chemical compound that’s used for cleaning. It’s a kind of mild antiseptic which can kill both bacteria and fungi. As such, you can use it to treat orchid rot of any kind, be it on the roots or on the leaves (or even in the crown). Here’s how it works:

  • Hydrogen peroxide comes in different concentrations. We recommend a concentration of 3%, which is strong enough to thoroughly disinfect your orchid’s roots, but not too strong.
  • You’ll need to wear gloves as you work with hydrogen peroxide.
  • With your orchid outside of its pot, trim away any severely rotten roots as per the section above.
  • Rinse your orchid’s remaining roots in room temperature water. This will get rid of any residual dirt, and ensure that the hydrogen peroxide cleaning process is thorough.
  • Spray the entirety of the root system with hydrogen peroxide. Use a regular spray bottle for the purpose (be sure not to use it again at some point in the future, mistaking it for water!) The hydrogen peroxide will make a fizzing sound and form bubbles on contact with the roots, which is normal.
  • Alternatively, bathe the orchid in hydrogen peroxide for just a minute. Again, you will hear a fizzing sound.

When you’re done, you can carry on with the rest of the steps in this process.

While this is the most effective way of dealing with rot, it isn’t strictly necessary. Following all of the other steps can be enough to fix the problem. If you don’t want to use hydrogen peroxide for whatever reason, we recommend following the rest of the steps, and occasionally checking on your orchid’s roots to see if the problem spreads or is contained. If it does spread, cut away any roots it spreads to.

4) Wash Your Orchid’s Pot

You cannot entirely get rid of the bacteria and fungus in your orchid’s pot. That’s because bacteria is introduced to the pot from the open air, from your hands, the tools you use on your orchid, and from water. The same applies to fungus, spores of which can float in through any open window.

What you can do, though, is at least get rid of the fungus/bacteria that caused the rot in the first place. This will make it less likely that the rot will come back. You don’t need to do anything special to the pot: just wash it with regular soap and water.

You could even consider doing this each week. Take the outer pot from the inner pot and wash it after you bathe your orchid. This won’t have any detrimental effect on your orchids, so long as you don’t leave a bunch of bleach in there! The only problem is that if you have a dozen orchids like I do, it might take a while…

5) Line The Bottom of The Pot With Gravel

If you want to keep lots of orchids, gravel is something you should always have to hand. It’s perfect for lining the bottom of your orchid’s pots.

Pour in about an inch-worth of gravel into the bottom of your orchid’s pot. Depending on the construction of the pot, it’s possible that there’s a section at the bottom with a narrow ring above it. This ring is there for the bottom of the inner pot to sit on, and the section underneath is for pouring gravel into. Not all pots have this, but you can put gravel in any pot anyway.

The point of doing this is that any water that dribbles out of the inner pot and into the outer pot will dribble down into the gravel. Your orchid’s roots won’t be able to access it, and the water won’t pool around the roots. Compare this to if the inner pot meets perfectly with the bottom of the outer pot: there’s nowhere for the water to drain to, so it just sits on and around the bottommost roots. Lining with gravel is therefore a good, low-maintenance way to avoid overwatering, because even if you do accidentally give your orchid too much water, it won’t have as much of an effect.

6) Change Potting Medium

When you buy an orchid from a supermarket, there’s a good chance that it’s in the wrong kind of potting medium. Orchids don’t need thick, dense potting mix that will hold onto moisture. If you’re picturing soil or manure, don’t! Orchids do better without any potting mix than they do with thick soil.

This is all down to how orchids live in the wild. Many orchids live on the sides of trees, without any soil around their roots at all. Others live in free-draining sandy mixes. Thick soils hold onto far too much moisture for your orchid to handle, so should never be used.

Repotting an orchid can be difficult. That’s because orchids form root balls, which are difficult to open and penetrate. But if you don’t do that, there will be lots of unsuitable soil left behind in between the roots. But you’re going to be pruning away rotten roots anyway, so this shouldn’t be a problem. Replace the potting medium with something more suitable like coconut bark, or even leave the roots naked for a while as the rot clears up.

7) Take a Little Time

This step is one that it’s easy to overlook, but which can make a world of difference. It’s something I learned from experience.

Like most everyone else, I’ve got a job. I also have hobbies I like to spend time on when I’m not working. Stuff like watering plants was always last on the list, because while I like my plants, watering them is a chore. There are a lot of them.

After a while I noticed that they weren’t in the best of health, and it was for a few different reasons. One had root rot, thankfully not too seriously. Others I realized I’d never repotted from the original mix they came in. Others had two, three, or even more basal keikis they were so unhappy. I figured either I should take better care of them, or stop taking care of them at all—I went for the former option!

To stop watering and caring for my plants being such a slog, I decided to make it into me-time. Just relax, and let the job take as long as it might take. I applied this to every sense in which I take care of my orchids: checking them for rot, watering them, checking for new growth, training flower spikes, repotting and so on. I found that when I just relaxed and enjoyed the time I was spending, it didn’t feel like a ‘job’ at all. Or you can put some music on, some TV, a podcast—whatever you like. Just take the time to water your orchids properly, check them for rot and check their overall general health, and you can easily avoid problems like these.

Root rot is one of the easier kinds of rot to fix, but you have to be thorough when you do. So, can you fix root rot? Yes—but only if you follow each step carefully, and are prepared to wait a while for your orchid to fully recover.