Knowing how to fix root rot is something anyone with potted plants may need up their sleeve, especially if you're a serial overwaterer. Root rot is easily one of the most common houseplant problems you're likely to encounter. This guide will help you recognize the symptoms before it's too late, then explains how to treat root rot. Plus, you'll find tips for helping droopy houseplants bounce back after a bad case of rot, and for preventing the problem in the first place.
What is root rot?
Root rot is exactly like what it sounds like. A plant's roots start rotting and can no longer absorb water effectively. Most often, root rot is caused by overwatering or poorly draining pots and potting mixes. Overly saturated soil deprives plant roots of the air they need to grow. If conditions don’t improve quickly, waterlogged roots start to die, and rot spreads throughout the plant.
Although overwatering is the most common cause of root rot, it can also develop due to harmful soil-dwelling bacteria or fungi, such as fusarium and pythium. These plant pathogens thrive in overly damp soil and are spread by fungus gnats, which are attracted to consistently wet potting mixes and decaying plant matter.
What does root rot look like?
If you’ve ever had a houseplant that seemed wilted but looked worse every time you watered it, your plant might have been a victim of root rot. Although a few plant pests and diseases cause houseplants to wilt, develop yellow leaves, and suffer from leaf drop, root rot does all of these. Plants may be stunted, and their leaves can appear dry, yellow, or pale with brown blotches. This appearance prompts many plant parents to water their plants more, which is a bad idea because extra water causes root rot to spread.
Because many root rot symptoms mimic other plant problems, the best way to positively identify root rot is to remove the affected plant from its pot and inspect its root system. Healthy plant roots should be firm and usually white or cream in color (although some plants naturally have dark roots). However, if plants have black, mushy, or smelly roots that crumble when you touch them, root rot is likely at work, and you need to act fast to salvage the plant.
How to Treat Root Rot
Damp conditions only make root rot worse, so if you suspect that your houseplants are struggling with rot, you first need to stop watering and reassess your watering schedule. After the soil dries out a bit, plants with mild root rot may recover on their own without any additional intervention. However, if you have plants with advanced signs of rot, the following treatment steps will help.
1. Remove the pot and soil.
Carefully lift the plant from its pot and brush away as much potting mix from the plant’s roots as possible. Then, rinse the roots to remove the rest of the old potting mix and assess the damage.
Plants with moderate root rot often improve with treatment. However, if root rot is severe, the plant may not recover.
If you suspect your plant won’t recover, salvage what you can by propagating new plants from stem or leaf cuttings taken from the doomed plant.
2. Trim away damaged roots and leaves.
After removing as much soil as possible, clip away all the damaged or mushy plant roots with clean garden shears or scissors. Be aggressive with this; rot can spread from infected roots if you don’t remove them.
After you clip off as many roots as needed, prune away some of the older and lower leaves on the plant so the smaller root ball won’t have as many leaves to support. Removing some leaves helps your plant recover quicker.
3. Repot the plant.
When the roots are all cleaned up, repot the plant in a clean growing container with fresh potting mix. Don’t be tempted to reuse the old potting mix, because old soil often contains fungal spores that re-infect plant roots. You can use a new pot or an old growing container, but make sure the planter you choose has plenty of drainage holes so root rot doesn’t reoccur.
How to Prevent Root Rot
While plants can often recover from root rot, preventing root rot is always the better option. Fortunately, root rot is relatively easy to avoid if you follow these simple tips:
1. Research plant care requirements.
Some plants need more water than others, and low-water plants, like cacti and succulents, are more likely to develop root rot in moist soil. However, if you study the specific care needs of the plants in your collection, you can adjust your watering techniques and provide individual plants with the perfect amount of water.
2. Check the soil before watering.
If you frequently overwater houseplants, you may want to invest in a soil moisture meter, which lets you know when it’s time to water. For a lower-tech solution, you can test the soil before watering by inserting your finger into the potting mix around the base of the plant. Most houseplants grow best if they’re watered when the top 1 to 2 inches of soil feels dry. If the soil is still damp, hold off on watering until it feels dry.
3. Select a well-draining potting mix.
Garden soil is not recommended for container growing because it tends to compact down in a pot and doesn’t allow water to flow through as well. Instead, use a potting mix with added sand, vermiculite, or perlite to boost drainage and shield the plant roots against rot.
4. Use growing containers with drainage holes.
Terracotta pots with drainage holes are a good choice for most indoor plants because they allow water to trickle away quickly and are more porous, which helps wick moisture away. Self-watering planters, plastic planters, and pots without drainage holes are more likely to cause root rot, so you may want to avoid them, especially if you struggle with overwatering.
If you use plant saucers or plates under your pots to catch water, empty the extra water out after watering so that the plants aren’t sitting in moisture.
5. Make sure the plants receive enough light.
Plants use water during the photosynthesis process. However, plants don’t absorb water readily if they don’t receive enough light. Providing your plants with the right amount of light can boost photosynthesis rates and help plants absorb water faster.
6. Adjust the watering schedule as needed.
Plant watering needs can vary throughout the year, and watering should be adjusted accordingly. For example, plants need less water in humid weather and during the winter when the days are short and light levels are low.
