How to identify and treat pesky root rot in your houseplants (2024)

• Root rot is a common disease that can impact indoor and outdoor plants.
• The most common cause of root rot in houseplants is overwatering.
• Diseased roots will look darkened and mushy, and leaves and stem can appear yellow and wilted.

All plant lovers, from the most experienced green thumbs to the first-time plant parents, have faced what is known to be the number one killer of houseplants — root rot. This disease may seem like it's game over for an infected houseplant, but with the right treatment and preventative steps, root rot can become a worry of the past.

Erin Marino, editorial lead and plant expert at The Sill, shares her best tips on how to identify root rot, what steps to take in preventing it, and how to save a plant from the damage caused.

How to identify root rot

Root rot may often be overlooked because the disease occurs underneath the soil, so symptoms might not show right away on the foliage of the houseplant. Marino says that wilted, mushy stems and browning or yellowing leaves can be a simple way to identify root rot.

To truly know if a houseplant is suffering from root rot, check its roots and soil — if the roots are darkened or black and mushy, and the soil is soggy and moist, root rot is probably the cause.

"If the root rot is left untreated, the root system could rot and decay completely, leading to the untimely death of the plant," says Marino. "And while all plants can be susceptible to root rot, it is most common in houseplants due to overwatering," says Marino.

What causes root rot?

While some cases of root rot are caused by fungi due to waterlogged soil, the most common cause of root rot is overwatering. "As humans, we're inclined to stay hydrated and could even argue 'the more, the better' when it comes to water, but that's not the case for most plants," says Marino. "If they are flooded with too much water, and their surrounding potting soil is left wet for too long, it can cause root rot."

When water sits at the bottom of the pot, it drowns and rots the roots, preventing them from getting the oxygen they need in order to grow.

"When watering, try to be mindful of the amount of water you're using (aim for about one-third or one-fourth the volume of the planter), or opt for a planter with drainage holes," says Marino.

While root rot is most common in houseplants, it can affect outdoor plants in the garden due to usually heavy rain and/or lack of drainage. According to Marino, root rot or corresponding fungus in garden plants could spread and affect nearby plants.

How to get rid of root rot and save a plant

The main way to get rid of root rot involves repotting, so it is important to be sure that root rot is the cause of the issue before you begin. Repotting a plant too much can shock a plant, especially right before and during growing seasons when plants are most vulnerable.

"Once you've noticed signs of root rot, unpot your houseplant and get a good look at the root system," says Marino. "A plant with root rot will have roots mushy to the touch, with some roots even falling off into the surrounding soil, while a slightly overwatered plant will still have some flexibility and firmness to its roots."

If the entire root system is black and mushy, it's best to discard the plant. However, if even just a couple of roots are white, firm, and somewhat flexible, the houseplant can be salvaged and its health restored.

Before repotting, Marino instructs to remove the plant from the pot it's in and clear all the rot and dying leaves. "First, trim back the root system to the best of your ability, removing the majority of rot and mushiness," says Marino. "Next, clean up the foliage above, removing any yellowing or dying leaves, and lastly, repot your plant in fresh, dry potting mix."

How to prevent root rot

The first steps in preventing root rot are to adjust watering frequency and to be mindful of watering potted plants, especially if the pot does not have a drainage hole. Marino recommends lining the bottom of these pots with lava rocks or pumice, layered on top with potting soil to create crevices for excess water to pool into.

"Well-draining potting mixes can also be a great option for root rot prevention and of course letting plants dry out between waterings," says Marino.

To avoid overwatering, Marino suggests always letting the soil of houseplants dry out before watering again. Maintaining a consistent watering schedule can also be key in practicing patience and moderation when it comes to plant care.

In the garden, Marino also advises to check for proper drainage. For outdoor potted plants, avoid leaving them uncovered in the rain if the pot doesn't have drainage holes. Just like indoor houseplants, well-draining soil in the garden can also prevent root rot.

"If you can't improve your garden's current soil, build raised beds and fill those with well-draining soil," says Marino. "Avoid using potting mixes or soils meant to retain moisture, and don't transfer impacted plants from one part of your garden to another as you may unknowingly transfer the fungal root rot."

If overwatering is still an issue, choosing plants that prefer higher humidity and moist soil can be a method in preventing root rot. Boston ferns, spike moss, and cyperus are all good options for those who tend to drown their plants.

Insider's takeaway

Root rot is a common plant disease usually identified by darkened or black, mushy roots and browning, wilting leaves and stems. To salvage a plant with root rot, removing all diseased portions of the plant and repotting it in fresh soil may give the plant a new chance at life. With well-draining soil, adjusted watering frequency, a pot with a drainage hole or raised garden beds, and waiting for a plant's soil to dry out, avoiding future root rot will be a breeze no matter what stage of plant parenthood you're in.