Showing aerated potting mix that helps to Prevent Root Rot in Potted Plants

How to Prevent Root Rot in Potted Plants (Must Read)

Root rot is one of the worst things that can happen to a potted plant. Unfortunately it’s also one of the most common causes for plants in containers dying. If you’re not able to detect it early enough to treat root rot, your plant is most likely going to die from it. Often, by the time you’ve spotted the issue, & the root rot is already advanced, it’s usually too late to save the plant. In this article, I’m going to share with you everything you need to prevent root rot and even share with you the way I treat my own plants and save many of them from almost certain death.

Here’s how to prevent root rot in potted plants:

  • Before you buy your plant, check its root ball, which should be healthy
  • Prevent overwatering
  • Choose a pot with adequate drainage
  • Replace soil about every year

Some newer indoor gardeners might not be familiar with root rot, but you’re about to be. In this extensive guide, I’ll tell you everything about this plant disease that kills so many houseplants prematurely. From what root rot is to ways to treat it and more on how to prevent it, your plants should be a lot healthier going forward!

What Is Root Rot? What Causes It?

To explain what root rot is, I first have to talk a little about plant anatomy. For new readers of Indoor Plants for Beginners especially, this information will come in handy.

The parts of your plant that are above the soil–such as the stems, petioles, leaves, flowers, branches, fruit, etc.–are only a portion of the plant itself. Underneath that, deep in the soil, are the plant’s roots.

Think of the roots as akin to a human’s heart; they’re what keep the plant alive. Roots, unlike the heart, can grow, sometimes detrimentally.

For example, I talked recently about plants becoming rootbound. This means the roots have so little room that they begin encircling the interior of the pot over and over again.

Removing the pot from the plant thus becomes extraordinarily difficult. Oh, rootbound plants are also at risk of death as the roots become too large for the plant to handle, so it’s a bad situation all around.

Let’s say your plant has a healthy root system, nothing rootbound here. When you water your plant, the water travels through the soil and reaches the roots, nourishing them and sustaining their growth. Yet what if you happen to water your houseplant too much?

The plants roots survive on two things, water and oxygen. If the soil is aerated and moist, then your plant’s roots should have a steady supply of both. By watering the plant too heavily, also referred to as overwatering, you inundate it with water and prevent oxygen from reaching the roots.

If you’ve ever been underwater and felt like you couldn’t breathe, this is the same thing your plant’s root system is experiencing. You’re drowning the plant with water, and thus root rot takes hold.

To begin to understand what root rot is, you only have to look at the name. The roots are oversaturated and soggy.

Plant roots that are suffering from root rot are oxygen-deprived. Once the roots have become so overwatered and deprived of the proper balance of oxygen and water they go from being firm, thick, and white, to becoming thin, flimsy, and black.

Very often, a plant’s root system that has suffered root rot will take on a distinct odor that smells rank or putrid. If not putrid then a smell that reminds you of more of rotten garbage than soil and a plant.

Since you don’t see the roots of your houseplant all that often, it’s typically not until the signs of root rot have spread up above the soil line into the base of the plant, up into the rest of the plant that the person caring for the plant notices something is wrong.

If you recall from the intro when I mentioned that root rot kills a plant from the inside out, this is what I was referring to, your plant may begin wilting or leaning.

At the later stages, a plant’s previously healthy green leaves become brown or even black. By the time your branches or leaves are beginning to suffer it’s often too late to save the plant with usual care.

If your plant is afflicted with root rot, is it necessarily going to die? It’s hard to say. I’ll talk later about how you can try to fix root rot, but it depends on how far along the plant disease has gotten. If it’s to the point where your plant is sagging and has become discolored, your poor houseplant may be too far gone.

How to Prevent Root Rot in Your Potted Houseplants

Start with Healthy-Rooted Plants

If you were buying a car, you wouldn’t ignore the undercarriage during your visual inspection, right? Yet you would be surprised how many people do the same when purchasing plants. You need to give your plant’s undercarriage a look too.

I’m not suggesting you rip every plant out of its pot at the gardening supply store. Houseplants don’t particularly like being removed from their pots, as it can induce stress. Plus, you’ll probably get kicked out of the store.

Here’s what I do recommend you do the next time you buy a plant (in person). As you browse the store’s selection of plants, find one or two that you really like. Then, between those few, pick the one that you want to own the most.

Ask someone at the store, ideally a manager, if they could show you the plant’s root system. You can similarly request if you can take a look yourself.

No matter who does it, it’s advisable to not follow through with the purchase until you see the root ball. You would hate for one of your first plants to die of root rot because, unbeknownst to you, the disease was already spreading while the houseplant sat on the gardening supply store’s shelves.

That can be a very discouraging first foray into indoor gardening. Not to mention, without looking at the root system of a plant you intend on purchasing will allow you to get a much better idea of the care or lack thereof a plant has endured prior to you buying it.

As a side note: I’ve often found that a plant I was inspecting for root rot at a store actually had a bug problem. If I had not inspected the plants root system before buying the plant it would’ve likely infested the other plants in my home that I was planning on placing it next to when I got home.

What are you looking for when you inspect the root system? A healthy root ball or root system. The roots should be white and firm. Dead and dying roots often feel mushy. If you spot any rotted bits or if the root system has a noticeable smell, pass on buying this plant.

Don’t Overwater Your Plants

How often you water your houseplants is also hugely important. That said, I know it’s not as easy as saying “well, don’t water them too much.” On average and depending on which houseplant you chose for your indoor garden, you should water them once a week to once a month.

As the growing season for your houseplant gets underway, typically in the spring, you should begin increasing how often you water it. In the summer when the temperatures are typically hot, continue the schedule.

When autumn arrives, you can scale back some, as most houseplant species are done actively growing (or are very close to being done) around this time. In the winter, you water the most seldomly, but that doesn’t mean you stop!

I always recommend the fingertip test for gauging when it’s time to water your houseplants. It’s a far more reliable method than watering your plant on a schedule. The above factors mean that sometimes your plant needs more water than what a schedule would allow and, in other instances, less.

So how do you do the fingertip test? Using a clean hand, put a finger about two inches deep into the soil. Do you feel moisture? If so, how moist are we talking about? If the soil feels a bit damp, then you’ll need to plan to water your plant in the next few days. With very moist soil, you can go a week or longer before watering again.

What if it’s been weeks, even close to a month since you’ve last watered your houseplant and its soil is still moist? While it depends on the species, with some houseplants, that’s perfectly normal. For example, succulents retain water for weeks at a time in their fleshy stems.

Ensure Your Plant’s Pot Has Adequate Drainage

One of the most fun parts about owning indoor plants is that you can grow them in containers, pots, hanging baskets, and sometimes even bowls of water. In all but the last vessel, the water must have a place to exit, typically through drainage holes.

Even if your watering schedule is perfect, your plant can still end up with root rot if the water within the pot remains.

I’ve talked about this on the blog, but some types of plant pots like those made of metal or ceramic don’t always come with holes. These pots are attractive, sure, but they’re also death traps for your plant. Well, unless you drill holes in, which can be a lot of effort.

For a list of indoor plants that don’t need drainage holes you can read: 13 Indoor Plants That Don’t Need Drainage

The mere presence of drainage holes isn’t always necessarily enough. The holes must be large in diameter for the water to flow through. You also have to check your plant’s pot about once a month for obstructions around the drainage holes.

For example, if you put rocks or stones in your plant’s pot (which you really shouldn’t do), they can shift and block the drainage holes. That’s one of the biggest reasons I advise against adding stones to a pot.

In severe cases, the plant’s roots can emerge through the pot’s drainage holes. This is a very overt sign that you need to move your plant to a larger pot ASAP, as it’s clearly more than outgrown the one it’s currently in.

Replace the Soil at Least Every Year

My last tip for preventing root rot is to change out your plant’s soil when the soil needs to be refreshed. Depending on the type of plant, the plants specific needs as well as the plants environment, can all affect how long a plants potting soil may last. the potting soil milage may vary.

Remember that repotting your houseplant because it’s outgrown its container isn’t the only time or reason that repotting your houseplant can be a good idea.

I’ve discussed repotting your houseplant many times before here on Indoor Plants for Beginners, but the potting soil you start with now will not remain in the same condition forever.

As the plant grows and you add more and more water and fertilizer to the soil, it can become compacted. With the soil particles so tightly-packed, your plant is in a precarious position.

As time goes on, old water that’s near the roots can get entrapped, encouraging root rot. The plant’s oxygen supply is also choked off.

The next time you go to water your plant, the water will get stuck nearer the top of the soil, never reaching the roots. The same thing will be true when you fertilize your plant, so now it’s deprived of nutrients too.

How often does your plant need new potting soil?

For plant species like the African violet and pothos, which are considered relatively fast growers, annual soil replacements are best. If you’re growing a snake plant or cacti, you can go up to two years before changing out the potting soil, as they grow more slowly. Knowing how fast your plant grows as well as its specific nutrient needs, can help you determine how often to replenish its potting soil and inform its fertilizing schedule.

Can You Fix Root Rot?

In short, yes! If less than half of the roots are affected by root rot then you have a chance at fixing the root rot or saving your plant.

That said, if more than half of the roots are affected by root rot the likelihood of saving your plant diminishes with almost relative percentages. Put another way, I would say that if 70% of the roots are obviously experiencing root rot then I’d give it about a 20-30% chance of being saved.

On the other hand, if 70% of the root system is good you have roughly a 60-70% chance in saving your plant. If you’re wondering why I add an additional 10% to each of the percentages it;’s because I try to account for he unknown factors.

If you didn’t realize it until you reading this article that one of your potted plants has root rot, you’ll definitely want to know what your options are.

Unless it’s a severe case, I always recommend trying to save your plant. If at the end of the day, it doesn’t work out, at least you know that you did all you could.

How do you know when it’s too late for your potted plant? As I mentioned, If the majority of the roots are black and mushy, then they’re almost entirely dead. With no healthy roots left to sustain the plant, its death is imminent.

If you see any healthy roots in the root system, then there’s work to be done. There are multiple teqniques for saving a plant from root rot. This method is one that I highly recomend to beginners as well as vetran plant lovers whe it comes to treating root rot.

Here’s how you get started.

Step 1: Removing the Plant from Its Pot

I’ve talked about freeing your plant from its pot several times in this article, but it’s not as easy as just giving the houseplant a hard tug. Since pot removal is stressful on a houseplant, as I said, you want to minimize any possible damage to the plant.

Purposely or accidentally removing leaves at this point will mean your root rot stricken houseplant will have less chance of survival. With even less leaves to help it absorb light for photosynthesis to assist in its struggle back to good health and producing new healthy roots.

It’s best if you have a second person to help you with the pot removal. One person should hold onto the pot and the other person should grip the plant at its base. Do not grasp its leaves, stems, or branches, as these will rip right off the houseplant. That will only stress it out more.

With a firm pull, yank the plant from its pot. Lift it gently and place it on a flat, even surface such as a table or even the floor. Put down some newspaper or plastic so you don’t get dirt and plant bits all over your home.

Step 2: Cutting the Dead Roots

Now that you can see which parts of the roots have been affected and which are still okay, you need to remove all the dead bits. To do this, standard gardening shears should suffice.

Hold a root in your hand, positioning your shears towards the part of the root that’s brown or black right near where the white root starts. Snip there, retaining as much white root as you can. Make sure no brown parts remain though.

Continue doing this across the rest of the plant, then sterilize your gardening shears. You can mix water (three parts) with bleach (one part) and soak your shears for a few minutes to disinfect them. This prevents any fungal diseases from spreading to otherwise healthy plants the next time you use those same shears.

Step 3: Replacing the Soil

Even if your watering habits caused the plant’s root rot, the condition of its soil might have worsened the problem. Your plant is already out of its pot, so take this opportunity to dump the current soil in there and add in new stuff.

Old soil doesn’t have to go in the trash, especially potting soil. You can aerate the soil, add some nutrients, and reuse it provided the soil was free of diseases (mostly fungal and bacterial diseases, not root rot). If that’s not preferable, you can always toss the soil into the compost pile.

Step 4: Watching and Waiting

Put your plant back in its pot and water it a little, as the soil is dry and the roots need it. Then it’s just a matter of time spent waiting and hoping for the best. If a few weeks have passed and your plant is doing fine, then it’s gotten through this episode of root rot mostly unharmed. 

I hope you feel I’ve informed your knowledge in preventing root rot a well as given you at least one tried and true method of treating this bane of caring for houseplants. Please consider sharing this article with a friend or three 🙂

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