Overwatering vs underwatering: how to tell the difference
Droopy leaves, yellowing foliage, a plant that just doesn't look right. Is this the sign of an underwatered or overwatered plants? Surprisingly, it’s difficult to always know – a glance at the leaves alone often isn't enough to tell which one you're dealing with.
Why do the signs overlap?
Both an overwatered and an underwatered plant can have drooping leaves or have yellowing leaves, because both conditions stress the roots in different ways. Too much water excludes the oxygen roots need from the soil, leading to extreme stress and, eventually, rot. Too little water leaves roots without the moisture they need to function and support growth. The plant's outward response to both kinds of stress often looks the same, even though the cause is the opposite.
Check below the surface
Rather than relying on appearance, push a finger a couple of centimetres into the soil or potting mix. Peat-free mixes in particular can look dry on top while still holding plenty of moisture beneath, which is one of the most common reasons plants end up overwatered. Lifting the pot helps too. A pot feels noticeably lighter when the soil is dry than when it's freshly watered, and that weight difference is one of the most reliable signs available.
How does overwatering and underwatering affect the roots over time?
An overwatered plant sitting in waterlogged soil is short on oxygen, which stresses the roots and can lead to rot if it continues. An underwatered plant, by contrast, often develops roots that stay shallow and concentrated near the surface, since they have little reason to grow deeper in search of water. Over time, a chronically underwatered plant becomes more vulnerable to drought stress, simply because its root system never had the chance to establish properly. That being said, the damage caused by underwatering is much easier to remedy than overwatering.
What to do if it's overwatered
Stop watering and let the mix dry out properly before the next one, checking with a finger in the potting mix or by weight rather than guessing. If the pot has been sitting in a saucer or decorative cover pot with no drainage, remove any standing water, since that alone can be enough to keep roots waterlogged even if you've stopped watering.
If the problem has been going on for a while and the plant isn't improving, it may be worth easing it out of its pot to check the roots; healthy roots are firm and pale, while rotting roots look dark, soft, and may smell unpleasant. Trimming away any rotten roots and repotting into fresh, well-draining mix gives it the best chance of recovering.
What to do if it's underwatered
Water thoroughly rather than giving it a token splash, but let the excess drain away fully. If the mix has dried out so much that it's become hydrophobic (meaning it's repelling water rather than absorbing it), water poured on top will run straight down the side of the pot rather than soaking in. A gentle pour, given time to absorb, repeated once or twice, rehydrates it more reliably than one heavy go.
Once you know what to look for, the next step is making sure you can act on it with the right amount of control. A good indoor watering can makes it easier to give a measured pour rather than a guess. Take a look at our indoor watering cans.
