Houseplants thrive in fairly harsh conditions, often surviving a fair bit of neglect from the inattentive gardener, but will suffer if not properly cared for. Too much attention, however, such as over-watering, presents its own problems. Root rot is a condition that is caused by fungi entering the plant through the feeder roots, causing a host of symptoms, and potentially causing the death of the plant.
Root rot is often caused by over-watering the houseplant, says Purdue University. Heavy soils that do not drain retain water around the roots, causing the roots to draw in too much water and drown in the soil. Houseplants require different amounts of watering according to their variety. Fungi is another cause of root rot. Water in the soil encourages the growth of fungi spores which enter the roots, causing the rot to occur.
Root rot causes a series of symptoms on a houseplant, including wilting and dropping leaves. Leaves that appear to be browning, losing their shape and drying out may indicate that not enough water is being drawn in by the roots. This often encourages over-watering, which exacerbates the problem. If root rot is the issue, the roots of the plant will appear brown and mushy when pulled from the soil. Tissue on the roots is easily pulled away from the plant.
Root rot will move through the entire plant's system within seven to 10 days, says the University of Minnesota Extension. Infected roots, once fully infected, fail to work properly. This causes a shortage of water to the leaves, causing the wilting and drop. Stem rot may develop as the fungi moves up the plant and the necrosis of the flesh spreads.
Once physical symptoms of root rot appear it is often too late to save the plant. If some foliar symptoms appear, though, check the roots and inspect for damage. If the damage is not excessive, it may be possible to save the plant. Pruning decaying roots, then soaking the good roots in a diluted bleach solution made of one part bleach to nine parts water will kill fungi still present. The plant is then planted into new, pasteurized soil.
As it is nearly impossible to stop root rot once it begins, and fungicides often prove ineffective, prevention is the key to reduce occurrence. Plants require watering according to the variety's needs. Using pasteurized, disease-free soil gives the plant a chance to grow in healthy soil. Do not use old soil when planting a new houseplant, even if the old soil did not cause disease in the previous plant. Some fungi are species specific and will only infect one plant while leaving others alone.