If a favorite plant in a garden has wilted and died despite frequent watering, it may have had root rot. Root rot is a common disease that happens to almost all plant species. Root rot in plants is usually a result of overly attentive watering or poor soil drainage, and it is easier to prevent than it is to treat. For most plants, root rot has already progressed to a deadly plant-killing disease once it shows signs above ground.
Root rot is a fungal disease that attacks the tiny feeder roots on a plant. When a plant has root rot, the first signs will appear underground. The roots of a plant with root rot will be large, brown, slimy and easy to separate from the plant. The plant will have few, if any, tiny roots, and several abnormally large roots may have grown to compensate for the missing roots. After root rot has progressed for one to three weeks, the plant will show signs of yellowing, wilting and stunted growth, and it may die soon after the infection becomes visible.
Root rot can be prevented by properly watering plants in well-drained planting areas. Know your plants' watering needs, and do not overwater them. Root rot is most common in indoor planting containers like pots that might have limited air flow around the roots to dry the soil. When using decorative pots with poor drainage or no drainage holes, replant the plant in a container with better drainage that you can fit inside the decorative pot. Add rocks or gravel to the bottom of the decorative pot before putting the repotted plant back inside the decorative pot. Using a second pot inside a decorative pot will ensure good drainage and air flow for the plant's roots.
Root rot can easily be spread through contaminated soil. Remove infected plants from shared planting areas if they appear to have root rot. For vegetable gardens, a planting distance of three feet between planting beds can help prevent a garden-wide spread of root rot. Don't re-use root-rot-contaminated soil unless you have sterilized it by heat or sun drying.
Not all of the soil you buy has been properly sterilized. If the bag of soil you bought has bugs or plants living in it, it was either not properly sterilized or the seal was broken, exposing it to pathogens and pests. The safest way to make sure soil is sterilized is to sterilize it yourself by heating it to between 160 and 180 degrees F for 25 to 30 minutes. Sterilizing soil can be done in small quantities in the microwave or conventional oven.
When disposing of a plant infected with fungal root rot, do not put it in your compost pile, in the trash, near your plant beds, or anywhere else the pathogens might infect other plants. Composting root rot infected plants will infect your whole compost pile with root rot fungi. The safest way to get rid of a plant with root rot is to burn it in a safe and controlled fire.