Seven Signs You Are Overwatering
When a houseplant dies, the most likely cause is not neglect. It is too much care, delivered from a watering can. Roots need air as much as water, and soil that stays wet for days drives the air out. The roots start to suffocate and rot, and a plant with rotting roots cannot take up water, so it wilts. Which, of course, looks exactly like thirst.
The earlier you spot overwatering, the easier it is to fix. Here are the signs we look for.
1. The soil is still wet days after watering
This is the clearest sign and the easiest to check. Push a finger two inches into the soil. If it is still damp three, four or five days after you last watered, the plant is getting more than it can use. Testing like this before every drink is also the simplest way to learn when to water. In large pots a finger cannot reach far enough, and a soil moisture meter is the more reliable way to tell what is happening down where the roots are.
2. Lower leaves turn yellow
Yellowing that starts with the oldest leaves at the bottom of the plant, while the soil is damp, is a classic overwatering signal. The leaves are often soft and limp rather than dry and crisp.
3. The plant wilts even though the soil is wet
This is the sign that catches people out. A droopy plant in dry soil is thirsty. A droopy plant in wet soil has damaged roots that can no longer move water to the leaves. Watering it again makes it worse.
4. The stems are soft or dark at the base
Gently squeeze the stems where they meet the soil. They should feel firm. Soft, mushy or blackened stems mean rot has spread from the roots upward. Plants that store water are especially prone to this. A snake plant with too much water often goes soft and translucent at the base of its leaves, and a ZZ plant shows yellowing stems and soft, rotting rhizomes below the soil.
5. Tiny flies around the pot
Fungus gnats are small, dark flies that hover around houseplants. Their larvae live in the top layer of constantly moist soil, so an infestation is almost always a sign the soil is not drying out between waterings. Let the top inch or two dry fully and their numbers drop fast.
6. The soil smells sour
Healthy potting soil smells earthy. Soil that smells sour, musty or like a stagnant pond has been wet for too long, and the roots in it are probably starting to rot.
7. Mold on the soil surface
A white or grayish fuzz on top of the soil is usually a harmless mold, but it only grows on surfaces that stay damp. Scrape it off and let the pot dry out more between drinks.
What to do
- Stop watering. Let the soil dry until the top two inches are dry, or longer for plants that like to dry out completely.
- Check the pot. It must have a drainage hole, and it must not be standing in a saucer full of water. A decorative pot with no hole is a common hidden cause.
- If the plant keeps declining, take it out of its pot and look at the roots. Firm, pale roots are healthy. Brown, mushy roots that slide apart are rotten. Cut the rotten ones away with clean scissors.
- Repot into fresh, dry mix and a clean pot no bigger than the root ball needs. Our repotting guide covers how.
- Water lightly and wait. A plant with fewer roots needs less water, not more, while it regrows.
How to stop it happening again
The underlying fix is to change your watering schedule from the calendar to the soil. Instead of watering every Sunday, check every Sunday, and water only if the soil is dry. Plants in cool rooms, dim spots and winter months need water far less often than plants in warm, bright rooms in summer.
Pot choice helps too. Terracotta dries out faster than plastic, which gives you a margin for error with plants that like to dry out. It is also worth knowing that a self-watering pot, which keeps soil constantly moist, suits ferns and calatheas but is a poor choice for any plant that likes to dry out.
If you are not sure where to start, learning how to water from first principles is the single best investment you can make in your plants. It is not difficult. It just means paying attention to the soil instead of the date, and remembering that when in doubt, waiting a few more days is almost always safer than watering.