How Often Should You Water Houseplants? A Simple Rule That Works

Almost every houseplant that dies indoors dies of watering, and more often of too much than too little. The reason is that people water on a calendar and plants drink on a set of conditions. A pot that takes five days to dry out in July takes three weeks in January, and a schedule that was right in summer is drowning the plant by midwinter.

The check that replaces the calendar

Push a finger into the soil to the second knuckle, roughly five centimetres. That is where the working roots are; the surface tells you nothing because it dries first and fastest. For most foliage houseplants, water when that depth is dry and the surface is dry. For succulents and cacti, wait until the whole pot is dry and then wait a few more days. For ferns, calatheas and other moisture-lovers, water when the surface has just dried and the soil below is still slightly damp.

Two things make this easier. Lifting the pot is a fast proxy once you know what a freshly watered pot feels like versus a dry one, and it works for plants you would rather not poke. A cheap wooden skewer pushed to the bottom and pulled out is the most reliable check of all: soil sticks to it and darkens it if there is moisture down there.

How to water when you do

Water thoroughly, not lightly. Pour slowly until water runs out of the drainage hole, then stop, wait a minute, and empty the saucer. This does two useful things: it wets the entire root ball rather than just the top, and it flushes out the mineral salts that build up from tap water and fertiliser and cause brown leaf tips.

A frequent light splash is the worst of both worlds. It keeps the surface permanently damp, which is where fungus gnats breed, while the roots at the bottom of the pot stay dry.

What changes the interval

1. More light means more photosynthesis, more transpiration and faster drying. A plant moved to a brighter spot needs water more often, not less.Light
2. Warm, moving air dries a pot quickly. Cold rooms and still air slow it down dramatically.Temperature and airflow
3. Terracotta breathes and dries out roughly twice as fast as glazed ceramic or plastic.Pot material
4. An oversized pot holds more wet soil than the roots can use, which is the classic cause of root rot after repotting.Pot size
5. Chunky, bark-heavy aroid mixes drain in minutes. Dense peat-based soil holds water for days.Soil mix
6. Most plants slow or stop growing in low winter light and need a fraction of the water they did in summer.Season

A starting point for common houseplants

These are starting points to check against, not schedules. Adjust from what the soil tells you.

• Snake plant, ZZ plant, cacti and most succulents. Let the pot go completely dry. Every two to four weeks in summer, as little as once every six weeks in winter.
• Pothos, philodendron, monstera, rubber plant. Water when the top third of the soil is dry. Roughly weekly in summer, every two to three weeks in winter.
• Peace lily, ferns, calathea, maranta. Keep lightly moist but never soggy. Often twice a week in summer. These are the plants worth a humidity tray.
• Orchids (phalaenopsis). Soak the bark thoroughly, then let it dry almost completely. Usually about once a week. Silver-white roots mean thirsty, plump green roots mean recently watered.

Reading the plant, not just the soil

Drooping is ambiguous on its own and only means something combined with the soil. Drooping in dry soil is thirst and recovers within hours of watering. Drooping in wet soil is root damage and gets worse if you water again, which is the trap that finishes off most overwatered plants: the owner sees the wilt, assumes thirst, and adds more water.

If you would rather not track any of this yourself, Identium builds a 28-day care plan for each plant in your garden based on the species it identified, and sends the watering reminder when that plant is likely to need it rather than on a fixed weekly loop.