Why Is My Houseplant Dying? A Troubleshooting Guide

I get asked some version of this question most weeks: a plant that was fine and now isn't, and no obvious reason why. The honest answer is that houseplants are much better at showing symptoms than causes, so the same droopy, yellowing leaf can mean three or four completely different things. Here's the logic I actually use on a visit, so you can start narrowing it down yourself.

Yellow leaves

The single most common symptom, and usually a watering issue rather than a light one. Yellowing that starts at the bottom of the plant and feels soft or mushy at the base is almost always overwatering, with the roots sitting wet and starting to rot. Yellowing that's dry, crisp, and spread more evenly across the plant tends to mean underwatering, or occasionally a pot that's become root-bound and can no longer hold enough water to see the plant through to the next watering.

Brown, crispy leaf tips or edges

This is usually about air, not water. Central heating, especially in winter, drops humidity dramatically in London homes, and many popular houseplants (calathea, ferns, peace lilies) are tropical species that expect much higher humidity than a heated flat provides. A pebble tray, a nearby humidifier, or simply grouping plants together to create a more humid microclimate all help.

Drooping that recovers overnight, then droops again

Classic underwatering: the plant is drinking through its whole pot between waterings and running dry before you get to it. If it stays droopy even after watering, that points the other way, towards waterlogged roots that can no longer take water up properly.

Small flying insects around the soil

Fungus gnats: harmless to you, but a reliable sign the compost is staying too wet for too long between waterings. Letting the top inch or two of soil dry out fully before watering again usually resolves it within a few weeks.

Sticky residue, tiny webbing, or a dusty white coating

Houseplant pests, likely scale, spider mite or mealybug respectively. These spread between plants quickly, so isolate the affected plant as soon as you notice anything, and treat promptly rather than waiting to see if it clears up on its own.

When it genuinely isn't fixable

It's rare that a plant is truly beyond saving, but it does happen, usually after prolonged root rot has gone unnoticed for months. Even then, there's almost always a lesson in what went wrong that makes the next plant in that spot last far longer.

If you've worked through this and you're still not sure, that's precisely what a houseplant health assessment is for: a proper, in-person diagnosis rather than a guess from a photo.