Why Orchid Roots Shrivel

Over-Fertilization

• Over-fertilizing an orchid can lead to burnt, dead roots. Orchid roots fare better when they lack fertilizer rather than have too much, as specimens that are exposed to too much fertilizer may exhibit yellow, shriveled or wilted roots and poorly looking leaves. A good rule of thumb for fertilizing orchids is "feed weakly, weekly," according to Kent Kobayashi of the University of Hawaii at Manoa's Tropical Plant & Soil Sciences Department. Flush pots with pure water to prevent the build-up of minerals in the plant if you suspect an orchid has been over-fertilized.

Over-Watering

• Kobayashi also notes that orchid roots can not tolerate over-watering or excessive moisture surrounding them, as they need adequate air circulation to survive. Healthy roots that are receiving the right amount of water appear firm, fleshy and white in color, often with plump green tips. Over-saturated orchid roots will turn yellow, wilt and shrivel before the leaves and flowers die.

Debris

• Orchid roots require adequate air flow to grow healthy and strong, and if they are in any environment that is laden with mud, bark and other debris, their ability to absorb water and nutrients properly may be hindered. The University of Tennessee Agriculture Extension Service notes that orchids should be repotted about every two years, giving gardeners the opportunity to rinse roots of debris with tepid water, place them in fresh potting mix and transfer them to a larger container that will allow for new, healthy root growth and air circulation.

Disease

• The St. Augustine Orchid Society describes several diseases that can lead to shriveled orchid roots. Bacterial soft and brown rot can cause orchid roots to shrivel, rot and wilt, and black rot is a purplish-black infection that starts in new roots and can cause the entire plant to quickly shrivel and wilt. Fungal root rot, a highly contagious disease caused by salt buildup from over-watering, over-fertilization or injury, will result in rotted, shriveled orchid roots.