What to Do When Orchid Roots Rot? A Detailed Guide to Remedies and Treatment

What to do when orchid roots rot: choose and mix a good orchid growing medium. The orchid growing medium must drain well and allow air through, moist but not waterlogged, dry but not parched. There are many special orchid growing media on the market today, and they are very suitable, such as Emei Mountain soil from Sichuan and expanded clay from Chongzhou; these all suit the habits of orchids well. Most orchids are not cold-tolerant and prefer cool shade, and their roots fear waterlogged conditions; a humus-rich, well-drained, slightly acidic soil is best.

Analysis of the Causes of Orchid Root Rot

1. Unsuitable environment

Insufficient light: Different orchid varieties need different amounts of light, but basically all need at least 4 hours. With insufficient light or dim conditions, the orchid plant's photosynthesis is weak, and the potting soil does not dry easily, so moisture remains for a long time and affects root growth.

Poor ventilation or too much ventilation: Without ventilation, the growing environment becomes too stuffy and hot, watering does not dry easily, and the plant's transpiration is also weakened; with too much ventilation, the water in the pot is quickly blown dry, and if it is not replenished in time, the water stored in the roots will slowly be used up and they will gradually dry out.

Insufficient humidity: Orchids like a relatively moist environment, and the roots also need relatively stable temperature and humidity. If it is too hot or too dry, orchid roots will rot.

So improve the environment and ensure suitable humidity. If an orchid keeps suffering root rot and its growth is poor, it is mostly because the environment is too dry, especially due to insufficient humidity in summer, so be sure to pay attention to controlling ventilation, light and humidity.

2. Wrong watering time and method

The time and method of watering change with the dry or wet condition of the potting soil and the temperature of the four seasons. Choosing different watering methods can keep the potting soil from becoming too dry or too wet.

So in summer it is best to water at night; by the next day the water will have drained away and the potting soil will not be too wet. Second, when watering, observe the plant's growth condition, and if it is not growing well, change the watering method and amount in time. In addition, when the temperature is too low (below 10°C) or too high (above 30°C), do not water, otherwise the orchid plant will suffer root rot from cold injury or heat injury.

3. Improper fertilisation

Orchids have fleshy roots, and the roots store a large amount of water, so they cannot absorb highly concentrated fertiliser. Especially when the roots have wounds, the roots will suffer fertiliser burn and rot. So when fertilising, apply thin fertiliser frequently. In addition, when using fermented organic fertiliser or slow-release fertiliser, do not place it too close to the roots, to avoid root rot.

4. It is sick

When an orchid plant is threatened by pests and diseases, root rot can result. In this situation people often only focus on pest and disease control and ignore the root rot. Killing pests is key, but you should also check whether the roots are rotten and take the plant out of the pot in time.

5. The growing medium lacks drainage and air permeability

Water is the source of all things. Orchids must have water to absorb and transport nutrients and carry out normal metabolism. Orchids are epiphytic-root plants. During their growth, a small part of their water comes from moisture in the air, while most of the water must be taken up from the water contained in the growing medium; orchid roots also need to absorb oxygen from the pores of the medium in the pot for respiration. If the medium in the pot drains poorly and the moisture content is too high, water will fill the pores of the medium, causing waterlogging. The pores of the medium are filled with water and lack oxygen, the roots suffocate from lack of oxygen, and over time the root function is gradually lost. At this point, because harmful pathogens invade and multiply, the roots will rot for this reason.

6. Non-clean water or unsuitable water pH

The water used for orchids must be clean and unpolluted. If unclean water is used, some harmful pathogens or toxins will erode and contaminate the orchid roots, causing serious disease of the root system and stems and leaves, and the roots will blacken and rot and the orchid plant will die. The pH of water used for orchids must be between 5.5 and 6.5. If the pH is below 5, it is on the acidic side, which will restrict the orchid roots' absorption of major elements such as nitrogen, phosphorus and potassium, and the orchid plant will lack major nutrients and its leaves will show yellowing. In an acidic environment, soil-borne pathogens such as root rot fungi are most suited to growing and multiplying, harming the root system and speeding up orchid root rot and death; if the pH is above 8, it is on the alkaline side, and alkaline water and medium will obstruct the absorption of trace elements needed for orchid plant growth, and the orchid roots and plant will gradually wither and die without the nourishment of trace elements.

How to Handle Orchid Root Rot

1. Choose and mix a good orchid growing medium. The orchid growing medium must drain well and allow air through, moist but not waterlogged, dry but not parched. There are many special orchid growing media on the market today, and they are very suitable, such as Emei Mountain soil from Sichuan, expanded clay from Chongzhou, and various special orchid soils from Guangdong; these are all good orchid growing media. You can also mix some leaf mould into these media to supplement insufficient fertility. You can also use local materials, such as weathered soil, crushed brick particles, crushed charcoal particles, crushed oak bark, etc., mixed with an appropriate amount of leaf mould; the effect is also very good, as it drains well and allows air through, retains moisture without waterlogging, and has a certain fertility. But note that the medium used must be non-toxic, sterile, unpolluted and free of parasitic insect eggs, otherwise it will also harm the orchid root system.

2. The water used to irrigate orchids must be clean. Polluted water and unclean water cannot be used. Many orchid books say that stream water and river water are most suitable for orchid growth, but most orchid growers live in cities and are not professional orchid garden operators, so it is very difficult to meet this requirement. From years of practice, the author has found that watering orchids with tap water also works very well. If conditions allow, put the tap water in a bucket or basin for a few days to let the chlorine in the water evaporate, which is even better. If you use spring water or pond water to water orchids, you should test the pH with pH test paper. If the pH is less than 5, alkaline substances such as lime can be added to adjust it; if the pH is greater than 6.5, hydrochloric acid, acetic acid, citric acid, etc. can be used to adjust it.

3. Regardless of what material the orchid pot is made of, the bottom of the pot must have appropriate holes, and it is even better if there are several holes around the lower part of the pot wall. In short, it must allow air through and drain water. When planting orchids, a layer of crushed brick particles or charcoal particles can be placed in the lower part of the orchid pot to help drainage and air permeability. The orchid pot should be placed so that air can circulate around the bottom and walls of the pot. If conditions allow, an orchid rack can be used to raise the orchid pot off the ground, which works even better.