How to tell if a houseplant needs water, and fix over- or underwatering
In short: Push a finger into the compost: if it's dry at your fingertip, and the pot feels light when you lift it, water until it runs out of the drainage hole, then empty the saucer. If the compost is still damp, wait, even if the plant droops.
By Abu Bakar SaadatPublished 28 October 20267 min readPublisher: Saadat Rafiq
✓ Reviewed by Sonia Abu Bakar, MSc Botany · 28 October 2026
IllustrationAt a glance
- Check
- Finger in the compost, then lift the pot
- Water when
- Dry at your fingertip (Clemson) or about 5 cm down (University of Maryland)
- How
- Until it drains from the hole; then empty the saucer (RHS)
- Main risk
- Overwatering: the main cause of death of potted plants (Clemson)
- Advice from
- RHS, Clemson, University of Maryland and Colorado State University extension services, read 28 October 2026
- Checked
- October 2026
Roots need water and air. When compost stays soaked, the air spaces fill with water, roots can't take up oxygen and they may rot (Clemson Extension, RHS). That's why Clemson calls overwatering the main cause of death of potted plants. The fix is simple: check before you water, every time, instead of watering on a fixed day (University of Maryland Extension, RHS).
Does your plant follow the usual rule?
Most leafy houseplants
Use the steps below: water when the compost is dry at fingertip depth and the pot feels light.
Cacti and succulents
They need far less water than most houseplants, so the finger check is not a reliable signal for them in the same way (University of Maryland Extension). Clemson says plants with fleshy leaves and stems need watering less often.
Large or very thin leaves, fine surface roots
These usually need water more often (Clemson). Check them first.
Just bought it
Flush it at its first watering: University of Maryland Extension says to leach every newly bought plant, pouring through plenty of water and letting it drain.
How to check and water
Push a finger into the compost.
Illustration: dry on top, still moist lower down Clemson Extension calls touch the most accurate check: push your finger in up to the first knuckle and water if the mix is dry at your fingertip. University of Maryland Extension goes a little deeper, about 5 cm (2 in). In a deep pot the deeper check tells you more, because most roots sit in the lower two-thirds of the pot (Clemson).
If you can't push a finger in that far, the mix may be too dense or the plant may be root-bound (University of Maryland Extension). A wooden skewer pushed to the bottom works too: moist mix sticks to it or darkens it (University of Maryland Extension).
You should see: dry, crumbly compost on your fingertip means water now. Cool, damp compost that sticks to your finger means wait and check again in a day or two.
Lift the pot to feel how heavy it is.
Illustration Dry compost weighs much less than wet compost (RHS, University of Maryland Extension). Lift the pot just after a good watering once, so you know what "full" feels like. After that, a quick lift tells you more than a glance. With clay pots you can also tap the side: a dull sound means moist, a hollow sound means dry (Clemson).
You should see: a pot that feels clearly lighter than it did after watering, together with dry compost at your fingertip.
Look at the compost and the leaves.
Illustration: dry compost pulls away from the pot Potting mix turns lighter in colour as it dries (Clemson), and dried-out mix shrinks away from the sides of the pot (University of Maryland Extension). Leaves give clues too, but they can mislead: a plant that is too dry wilts and turns grey-green, while a plant that is too wet also wilts, and its lower leaves yellow and drop (University of Maryland Extension).
Before you water: if the plant droops but the compost is still damp, don't water. Clemson warns that wilting caused by damaged or rotting roots gets worse with more water. Go to the overwatering fix below.
Water slowly until it runs out of the drainage hole.
Illustration Water the whole surface, not one spot, until water drains from the bottom (RHS, Clemson). That wets the lower two-thirds of the pot, where most roots are, and flushes out excess salts (Clemson). A small plant can go in the sink for this (University of Maryland Extension).
Bottom watering also works: stand the pot in a tray of water so the mix draws it up, then pour off what's left (University of Maryland Extension).
You should see: water dripping from the drainage hole, and the pot heavier when you lift it.
Let it drain, then empty the saucer.
Illustration Don't leave houseplants standing in water (University of Maryland Extension). Let the pot drain fully and empty any saucer that holds water (RHS). A wet saucer also invites fungus gnats (University of Maryland Extension).
You should see: a dry saucer and no water pooling on top of the compost.
Too much water or too little?
Both problems can make a plant wilt, so the compost decides, not the leaves (Clemson, University of Maryland Extension).
| What you notice | Too much water | Too little water |
|---|---|---|
| Compost | Still damp or soggy days after watering; water pools on top (RHS) | Pale, dry, shrunk away from the pot (Clemson, University of Maryland) |
| Leaves | Lower and inner leaves wilt or turn yellow and drop (University of Maryland, RHS) | Wilting, grey-green colour (University of Maryland); brown leaf edges (RHS) |
| Flowers and growth | Whole plant may collapse (RHS) | Buds and flowers drop, growth slows (RHS) |
| Roots | Black, mushy roots (Colorado State University Extension) | Root ball dry and hard to rewet (Clemson) |
If the compost has dried out completely
Very dry mix repels water: it runs down the gap at the side and out of the hole. Clemson gives two fixes. Water once, then again about 30 minutes later. Or stand the pot in a sink or bucket of water, take it out once the surface of the compost is moist, and let it drain completely. Peat-based mix that has dried right out holds less water afterwards (Clemson), so keep checking it with your finger as usual.
If you think you've overwatered
Stop watering, empty the saucer and let the top of the compost dry out (University of Maryland Extension, RHS). If the plant still droops in damp compost after a few days, or the leaves keep yellowing, ease it out of the pot and look at the roots. Colorado State University Extension says to cut away black, mushy roots and repot in fresh potting mix, at the same depth as before. Our repotting guide walks through that.
How to tell you got it right
- Water ran out of the drainage hole, and the saucer is empty again (RHS).
- The pot feels heavy when you lift it.
- A day later, a drooping plant has stood back up. If it hasn't and the compost is wet, see the overwatering fix.
- New leaves come through green and the lower leaves stop yellowing over the next few weeks.
If something goes wrong
| What happens | What it means | What to do |
|---|---|---|
| Water pours straight through in seconds | The root ball has shrunk away from the pot (University of Maryland) | Soak the pot, or water twice 30 minutes apart (Clemson) |
| Water sits on top and won't drain | Blocked hole or compacted compost (RHS) | Check the drainage hole; repot into fresh compost if needed |
| Plant wilts although the compost is wet | Roots may be damaged or rotting (Clemson, RHS) | Don't water; check the roots |
| White crust on the compost or pot, brown tips | Salt build-up (University of Maryland) | Flush with twice the pot's volume of water (University of Maryland) |
| Small dark flies around the pot | Fungus gnats, which breed in wet compost (University of Maryland) | Let the top dry out between waterings; see our fungus gnat guide |
Questions readers ask
Are soil moisture meters reliable?
Not very. Clemson Extension says their accuracy varies widely, and readings can be thrown off by fertiliser and the type of potting mix. Use one as a second opinion next to the finger and weight checks, not instead of them.
Can I water houseplants straight from the tap?
Usually yes, but the RHS suggests letting tap water stand in an open container for at least 24 hours first, and using it at room temperature. Never use water from a domestic water softener (RHS, Clemson). Acid-loving plants do best with rainwater (RHS).
Should I water less in winter?
Check more, not less. Plants in cool rooms need less water, but central heating dries the air and pots can dry out faster (RHS). In a cool room that stays above the plant's minimum temperature, many houseplants can go a week or two without water (RHS).
Why are the leaf tips brown?
Brown leaf edges can be a sign of underwatering (RHS), but salt build-up from tap water and fertiliser causes brown tips too, often with a white crust on the compost or pot (University of Maryland Extension). It suggests flushing the pot with at least twice its volume of clear water every four to six months.
Sources
We base our articles on the makers' official documentation.
- RHS: How to grow houseplants (no page date)
- Clemson Cooperative Extension, HGIC 1459: Indoor plants, watering (last reviewed 21 June 2024)
- University of Maryland Extension: Watering indoor plants (updated 10 March 2023)
- University of Maryland Extension: Symptoms of overwatering indoor plants (updated 13 March 2023)
- Colorado State University Extension, PlantTalk 1316: Houseplants, repotting (no page date)
