What causes tip burn in orchids? A detailed explanation of causes and prevention methods

Tip burn in orchids affects their ornamental value, also affects the healthy growth of the orchid plant, and can even endanger the life of the orchid plant. It is a thorny problem frequently encountered by orchid growers.

If the leaf tips of an orchid plant are scorched and withered, there is root damage to varying degrees, and there are multiple reasons for poor root growth. First, waterlogging damage, such as when the orchid pot is fine and dense in texture, so moisture evaporates slowly; when the growing medium is not coarse enough, so drainage performance is low; or when watering is excessive. Second, freezing damage: orchids are not tolerant of low temperatures and frost, and after the root tips are frostbitten, they lose the ability to absorb water and nutrients. When the temperature rises the following spring and light intensity increases, the leaf tips receive no nourishment and become scorched and withered. Third, fertilizer damage: planting orchids generally does not require base fertilizer. If organic fertilizer that has not been fully decomposed and disinfected is applied, it will ferment in the pot and damage the roots; especially overly dense fertilization will harm the orchid roots and cause tip burn. Fourth, high temperature damage: in a greenhouse or plastic tunnel, excessively high temperatures can cause the leaf ends, leaf margins and leaf tips to become scorched and withered; for orchid plants grown in narrow cylindrical pots, their root tips press close to the pot wall, and when the temperature is high the pot wall becomes hot and can scald the root tips, causing the leaf tips to become scorched and withered. Fifth, acid damage: in a medium that has not been repotted for more than two years, because acidic chemical fertilizers are often applied, the medium becomes acidic, which can also cause root rot. Sixth, hormone damage: some growers apply growth inhibitors to dwarf the orchid plant. This chemical has a long residual effect, causing the roots to turn black and lose function, so the leaves receive no nutrient supply, causing tip burn to occur, until the whole plant dies. Seventh, nutrient deficiency: some orchid growers increase the amount of nitrogen fertilizer to make the leaves dark green and promote more shoots, which throws the three essential fertilizer elements out of balance; the most common result is a relative potassium deficiency, with scorching and withering appearing at the leaf ends, leaf margins and leaf tips. Eighth, diseases: common root diseases include root rot, black rot, bacterial wilt and soft rot, etc. After a plant is infected, the roots lose function, causing the leaf tips to become scorched and withered one after another,

and then the whole plant dies.

The prevention and control methods for tip burn in orchids mainly include the following three points. First, to grow orchids, first grow the roots. Pot vessels with a coarse texture should be selected, and utensils that are specially made, tall and cylindrical with feet and with many holes in the pot wall should be used as much as possible; the medium should be as coarse as possible, and locally sourced mountain soil should be mixed with crushed brick particles, fired soil or disinfected China fir sawdust, etc., to enhance water permeability; watering should be done two or three days after the soil surface in the pot has dried, and fertilizer concentration should be low rather than high, with long intervals between applications, avoiding one-sided application of nitrogen fertilizer, and ensuring combined use of nitrogen, phosphorus and potassium fertilizers; for plants repotted at two years old, the seedlings can be lifted, the medium replaced, and a single application of 3000-fold white alkali water poured on to neutralize acidity. Second, pay attention to the surrounding environment for growing orchids. Poor ventilation or muggy, steamy conditions, relative air humidity that is too low or too high, and excessively strong direct sunlight are all unfavorable to their growth. When covering with plastic film on site in a simple plastic tunnel to prevent freezing, because moisture cannot be expelled and dampness cannot be absorbed, water droplets inside the film drip onto the orchid leaves and freeze there, as if the leaves had been scalded with boiling water. Although mild cases may recover, by late spring and early summer large areas of scorching and withering will gradually appear. Therefore, in this kind of environment, moisture-absorbing materials such as cloth, blankets, burlap sacks or straw curtains should be hung inside the tunnel. Third, prevent and control diseases. Infectious diseases mainly include tip burn disease, rust disease and iron cannon disease, etc., but the most headache-inducing for orchid growers is bacterial tip burn and head shrinkage. In fact, tip burn and head shrinkage are only surface symptoms; the source of the disease lies deep in the roots. Cutting off the scorched tips cannot fundamentally solve the problem. The pot must be thoroughly turned out and handled, the roots disinfected, and the source of the disease eliminated.