A lot of houseplant deaths get blamed on overwatering when the real fault is drainage: water that has nowhere to go, sitting around roots that need air as much as they need moisture. Whether your particular combination of pot, saucer and watering habit causes that problem is not always obvious from looking at the pot itself, because a pot with a hole can still trap water and a pot without one can still work perfectly well.
What the checker is working out
The Drainage Setup Checker takes what you tell it about your planter, your plant and how you water, and works out whether that combination lets excess water escape or leaves it sitting against the roots. It asks for the kind of detail a label never gives you: whether the pot has a drainage hole, whether you're using it with a saucer or a liner pot inside something sealed, and roughly how often you water.
It can be wrong. It is reasoning from what you describe, so a detail you leave out or get slightly wrong changes the answer. Treat the result as a starting point for checking your own setup, not as a verdict on it.
Why the same pot works for one plant and not another
A sealed ceramic pot with no hole is not automatically wrong. It is wrong for a plant watered on a fixed schedule into soil that never gets the chance to dry, because the water has only one place to sit. The same pot, used as an outer cover with the plant kept in its original nursery pot inside and watered carefully, causes no trouble at all. The checker is built around that distinction, because the material on its own never tells you the answer. The drainage guide sets out the full set of scenarios this covers, from pots with holes and saucers through to adding drainage to a sealed pot yourself.
The signs it is reasoning from
- Whether the pot has a drainage hole at all
- Whether a saucer or liner is in use, and how deep it sits
- How often you water and whether you let the top layer dry between waterings
- The plant's own tolerance for sitting wet, which varies a great deal between a peace lily and a succulent
What it flags once it has an answer
Where the setup looks like it will cause trouble, the result points at what to change. That might mean adding a layer of material under the soil, swapping a shallow saucer for a deeper one, or fitting a liner pot instead of planting straight into a sealed ceramic. Where the plant is a type that actively dislikes sitting in damp soil, such as a succulent or cactus, the same setup that suits a peace lily gets flagged as the problem.
If the plant is already showing symptoms
A drainage fault usually shows up before you go looking for it: yellowing lower leaves, a sour smell from the soil, or roots that feel soft rather than firm when you check them. If that has already started, checking the setup tells you why it happened, but it will not tell you how far the damage has gone or what to do about the plant itself. The Plant Health Checker is built for that part, taking the symptom and the plant type and ranking the likely causes, with any pot or drainage implications flagged alongside them.
Where to go from the result
If the result points to the pot being too large or too small for the drainage to work properly, the Pot Size Calculator gives you a specific diameter and volume to aim for instead. If it points to the material itself being a poor match for how you water, the planter materials guide sets out how terracotta, ceramic, plastic and the rest behave differently with the same watering habit.