When a plant needs water

So the check runs bottom up. Soil first, weight second, leaves last.

This is the ordinary case. The mix is dry at finger depth, the pot has lost weight, and the leaves are either still fine or hanging softly. The soil may have shrunk back from the wall of the pot.

Water now, and water properly rather than in sips. Small amounts wet only the top layer and leave the lower roots dry while the surface looks watered.

If the mix has dried out completely and water runs straight down the gap at the side, stand the pot in a bowl of water until the surface turns damp, then let it drain.

Drooping on damp soil is the case that costs plants their lives, because the reaction is to water again. Damaged roots cannot take water up, so the plant wilts in a wet pot and looks thirsty while it drowns.

The signs sit lower down. Yellow leaves at the base, a stem that feels soft just above the surface, water standing in the saucer or the cachepot, and a smell from the mix that was not there before.

Stop watering and lift the plant out of the pot. Firm, pale roots are healthy. Brown, soft roots that slip apart between your fingers are rotted and need cutting away before the plant goes into fresh mix and a clean pot.

Dry tips and brittle edges on a plant whose soil is damp are usually about the air around it rather than the water in the pot. Radiators, a heating season and a spot in a draft all dry the leaf out faster than the roots can replace what it loses.

Watering more in that state only puts the roots at risk. Move the plant away from the heat source, group pots together so the air between them stays damper, and stand it on a tray of pebbles and water if the room is very dry.

Hard tap water leaves the same brown edges on sensitive species over time. That one is about what is in the water rather than how much of it there is.

The two get confused because both end in a plant that looks tired. The difference is timing. A dry plant changes within a day and recovers within hours of being watered. A plant short on light changes over weeks and does not react to a watering can at all.

Light shows in the new growth. Leaves that come in smaller and paler than the older ones, long bare stretches of stem between them and shoots leaning hard toward the window all say the plant is reaching for light.

Stand where the plant stands and look toward the window. How much open sky you can see from there is roughly the light it gets. A yard further into the room is a much bigger drop than it looks.

A plant in dim light also needs less water, because it grows slowly and the mix stays damp for longer. Moving it closer to the window and watering it the same way as before is the combination that rots roots.

Water the mix, not the leaves, and keep going until it runs out of the drainage hole. That wets the whole root ball and carries built up salts out with it.

Half an hour later, tip out whatever stands in the saucer or the cachepot. Roots left sitting in water are the most common way a houseplant dies indoors.

Room temperature water is easier on roots than cold water straight from the tap. Filling the can the evening before is enough.

Bottom watering suits plants with fine hairy leaves and pots whose surface has gone water repellent. Stand the pot in a few inches of water, wait until the surface darkens, then take it out and let it drain.

No interval in days survives contact with a real home. A small pot in a bright warm room dries in a fraction of the time a large pot in a dim corner takes, and the same plant needs a different rhythm in July than in January.

Pot material matters too. Unglazed clay loses water through the wall, so those pots dry faster than plastic ones of the same size.

Plants with thick leaves or fat stems carry their own reserve and go far longer between waterings than thin leaved ones. Ferns and species from wet ground sit at the other end.

The habit worth building is the check rather than the schedule. Look at the plants on a fixed day, then water only the ones that come up dry.