Why do spider plant leaf tips turn brown and black?

Why do the leaf tips of potted spider plants turn black, dry up and shrivel? How can this be prevented?

When potted spider plants show withered, blackened leaves, from a cultivation standpoint there may be the following causes.

First, dry air, overly intense sunlight and excessively high temperatures. This situation mainly occurs in summer and autumn, because spider plants like to grow in humid, semi-shaded environments; once the air is too dry, the sunlight is unobstructed, and on top of that the temperature rises above 30°C, it is very easy to cause the leaf tips of spider plants to wither. If this is the case, the plant can be moved to a semi-shaded environment, the withered leaves cut off, and the leaf surfaces and surroundings sprayed with water frequently; the newly emerging leaves can then return to a normal state.

Second, waterlogged potting soil and rot of the fine feeding roots. Because the potting soil is compacted or too heavy and sticky, or because watering is too frequent and too heavy, the fine feeding roots of the spider plant rot, and thus the root system's ability to absorb water drops sharply, causing the tips of the spider plant leaves to turn black first and the edges to curl inward. If this is the case, the plant can be taken out of the pot, part of the old soil shaken off, the rotted parts of the root system cut away, and it can be replanted in clean, damp sand, keeping the sand moist but not spraying too much water; after new white tender fine roots have been induced, it can then be replanted in fresh, fertile potting soil.

Third, not repotting for a long time, so that the roots grow right up against the pot wall; in a hot, dry or cold environment this easily causes the root tips to shrivel and die, making them lose their proper absorbing function and thus causing the leaf tips to dry up and shrivel. If this is the case, the plant can first be tipped out of the pot, the already dead leaves or the dead parts of the leaves cut off, part of the old soil picked away, some aged or dead roots removed, and it can be replanted in fresh potting soil, then placed in a cool, moist, semi-shaded environment; take care to spray more and water less, and the plant's newly emerging tender leaves can then return to normal.