How to tell if a houseplant is overwatered or underwatered

A drooping plant with yellow leaves is hard to read. Too much water and too little water can cause the same first signs. The plant looks sad, and the next move is a guess.

Stop guessing. Three checks give a clear answer: the soil, the weight of the pot, and the roots.

Check the soil first

Push a finger into the soil up to the second knuckle, about two inches down. A wooden skewer or a chopstick works too. Pull it out and look at it.

If the skewer comes out dark and damp with soil stuck to it, the soil is wet. If it comes out clean and dry, the soil is dry.

Now match the soil to the symptoms:

• Wilting plant, wet soil. The roots are likely damaged and cannot take up water. This points to overwatering or poor drainage.
• Wilting plant, dry soil. The plant is thirsty. This points to underwatering.

That one pairing solves most cases.

Lift the pot

Pick up the pot right after a full watering. Note how heavy it feels. Pick it up again a few days later.

A pot full of wet soil is heavy. A pot of dry soil is light. After a few weeks, the weight tells you when to water without any other test. This works best in small and medium pots.

Signs of overwatering

Overwatered plants often show these signs:

• Soil stays wet for many days after watering.
• Lower leaves turn yellow and drop.
• Stems feel soft or mushy near the soil line.
• The soil smells musty or sour.
• Small flies (fungus gnats) hover around the pot.
• Leaves look limp even though the soil is damp.

Some plants also grow small blisters or corky bumps on the undersides of leaves when they take in more water than they can use. The leaf itself is not sick. The watering needs to change.

Signs of underwatering

Underwatered plants show a different set of signs:

• Soil is dry deep down and pulls away from the edge of the pot.
• Leaves curl, droop, or feel thin and papery.
• Leaf edges and tips turn brown and crisp.
• The whole plant perks up within hours of a good watering.
• The pot feels very light.

Crisp brown tips alone do not prove thirst. Dry air and mineral buildup from tap water or fertilizer can cause them too. Read the tips together with the soil.

Look at the roots when you are unsure

Tip the plant out of its pot. Hold the base of the stems and slide the root ball out. Check the roots.

Healthy roots are firm. They range from white to tan. Rotted roots are brown or black, soft, and often smell bad. They may fall apart when touched. A tight mat of dry, pale roots with hard, dusty soil points to a plant that has been too dry.

How to fix an overwatered plant

Stop watering. Move the plant to a spot with bright, indirect light and good air flow.

If the soil is soggy and the roots look healthy, let the soil dry out. Check it every few days with the skewer.

If the roots are rotted, repot. Remove the wet soil. Cut away every brown or mushy root with clean scissors. Leave the firm roots. Repot into fresh, dry potting mix in a pot with a drainage hole. Water lightly once, then wait until the top few inches of soil are dry before watering again.

Check the saucer and any decorative outer pot. Water that sits at the bottom keeps the roots wet. Empty it after each watering.

How to fix an underwatered plant

Water until liquid runs out of the drainage holes. Wait ten minutes and empty the saucer.

Very dry soil can shrink and repel water. The water then runs down the gap along the pot wall and out the bottom. If this happens, set the pot in a sink or tub with a few inches of water. Let it soak for 20 to 30 minutes. The soil will take up water from below. Lift it out and let it drain.

Do not flood a dry plant over and over in one day. One thorough watering is enough. Leaves that are already crisp will not turn green again. New growth will come in healthy.

Plants need different watering

No single schedule fits every plant. Succulents, snake plants, and ZZ plants prefer the soil to dry out between waterings. Ferns and calatheas prefer soil that stays lightly moist, but not soggy.

Light and season change the need as well. A plant in a bright window uses water faster than one in a dim corner. Most plants grow less in winter and need water less often.

Water when the soil says so, not when the calendar does. Use the finger test, lift the pot, and give the plant a drainage hole. These habits prevent most watering problems before they start.