Several fungi that invade the roots of houseplants lead to root rot, a serious and deadly plant disease. You -- or your kids, if one of their chores is keeping the plants watered -- might be making this problem worse by giving the houseplants too much water. Pots without drainage holes also contribute to root rot, but there are some simple, natural ways to help get rid of it.
1. Signs of Trouble
Root rot affects the roots first, but you're not likely to notice the problem until the leaves begin to show signs. Look for wilting or browning leaves, especially if they're on one side of the plant -- a quick way to diagnose possible root rot on that side. Your plant might not grow as fast as it should, or blooming plants could stay green without flowering. Uncover the roots and scrape the outer edge gently with the side of a trowel to expose the roots. Healthy roots are white and firm, while rotted ones are brown and soft.
2. Act Quickly
If most of the roots aren't affected, it's likely you can save your plant. Remove it from the pot and trim away all brown or soft roots, removing them as close to the plant as possible. Rinsing the remaining roots removes all traces of the soil, which could possibly be contaminated with the fungus. Wash your hands and pruning shears thoroughly, using a solution of 10 percent bleach on your shears, to prevent spreading the fungus to other plants. To make a 10 percent solution, mix 9 parts water with 1 part household bleach.
3. Clean the Soil
Only repot your plant into sterilized soil. Many commercial potting mixes are sterile and disease-free, so you can simply replace your existing potting soil with some fresh medium. Use a well-draining soil, such as one containing perlite or bark chips. To reuse your existing soil, you must pasteurize it by spreading it about 2 to 3 inches deep on a disposable baking pan and cooking it in the oven at 180 degrees Fahrenheit. When the center of the soil reaches 180 F, as measured with a meat thermometer, cook it for 30 minutes at that temperature to kill all the fungus and bacteria living in the soil. Or, cook it in the microwave on high for 15 minutes. After the soil cools, it's safe to use. Make sure you sanitize your thermometer and any kitchen equipment before you use it again.
4. Change the Pot
The pot could also be part of your problem. If the pot has only one drainage hole, it might not be enough. Drilling more drainage holes helps ensure there's no standing water in the pot to encourage fungus growth, or you can replace the pot with one that has more holes. If you're reusing your old pot, scrub it with a 10 percent bleach solution, rinse it well, then let it soak in the solution for about 30 minutes before adding soil and repotting your plant. Don't add gravel to the bottom of the pot because it can hold water in the crevices instead of letting it drain.
- University of Illinois Extension: Damping-off and Root Rots of House Plants and Garden Flowers
- Mississippi State University Extension Service: Hints for Healthier Houseplants
- University of Nebraska Lincoln Extension in Lancaster County: Indoor Houseplants and Root Rot
- University of Wisconsin Extension: Root Rots on Houseplants
- University of Minnesota Extension: Root Rot of Houseplants
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