The reasons why plants die are legion. There are nine reasons which account for the bulk of plant failures.
Water is essential to all life. Failures to provide sufficient water at sensible intervals during the season of the plant’s growth will lead to thewilting and the plant’s eventual death.
Probably many more indoor plants die from over-over-watering.than any other cause, especially in winter time. The leaves of the over-watered plants flag and it is assumed that lack of water is the reason. A thorough watering is given and the plant succumbs. Both over-watering and under-watering cause leaves to wilt, and it is vital that the two should not be confused. Too much watering tends to cause a yellowing of the leaves which remain soft and pliant. Dryness is more likely to show in the shrivelling of the leaves which become brown, brittle and dry. Over-watered often become covered in green slime caused by algal growth. Read more on how to deal with
Geraniums and a few other plants seem to thrive on strong sunshine. Even so, they are happier if the pot and soil surface are protected from the heat. Many plants will not tolerate such conditions. Always shade the pot and soil surface to prevent baking which will kill the.
4. Sharp temperature drop at night
A plant may be hardened to a comparatively low temperature but sharp fluctuations are a different matter. Frost is almost always fatal. Never leave plants on a window sill after drawing the curtains at night in cold weather. A frosted plant may sometimes be rescued by spraying it at once with cold water.
5. Hot dry air
Most artificial home heating dries out the ambient atmosphere. Such dry air is unsuitable to most indoor plants. Read more on how to provide humidity.
Gas and other fumes are most likely to be toxic to plants.
7. Lack of light
Almost all plants need some light and will die without it.
These are invariably accompanied by sharp temperature changes. Very few plants will tolerate such conditions if they are acute. Even plants which do survive them will not do as well as they would otherwise.
This can result in residues of unwanted chemicals building up in the soil. Eventually the concentrations become unacceptable and often toxic. Underfeeding is a much lesser risk and is usually rectifiable. Read more on feeding houseplants.