How to water indoor plants?

What is the watering frequency for indoor plants?

Watering frequency varies according to species, pot size and room temperature. For example, a Calathea or a Spathiphyllum (peace lily) requires a consistently moist potting mix, whereas a cactus or a Sansevieria can tolerate several weeks of drought.

As a rule, most houseplants need water every 7 to 10 days in summer and every two to three weeks in winter, when growth slows.

A good indicator is to touch the surface of the potting mix: if the top 2 centimetres are dry, water is needed.

To make comparison easier, here is a table of water needs for common houseplants.

How much water to give to indoor plants?

When watering green plants, make sure to moisten the entire root ball without waterlogging the potting mix. The correct technique is to:

1. Pour water slowly until a few drops run out of the pot’s drainage holes.
2. Then, empty the saucer after about ten minutes to prevent roots from sitting in stagnant water.

A sign of successful watering: potting mix is moist throughout, but remains supple to the touch, never compacted or waterlogged. Too little water wets only the surface, leaving roots dry, while repeated overwatering causes foliage to yellow. The larger the pot, the more water the plant needs, but always in proportion to its size and species.

Common mistakes to avoid

Several mistakes regularly occur when watering indoor houseplants. Knowing them helps preserve plants’ health:

• Watering according to a fixed schedule : watering always on the same day (or at the same time), without checking the potting mix, can cause overwatering or underwatering. Plants’ needs change with the season, temperature and light. Checking the surface of the potting mix remains the best guide.

• Using unsuitable water : cold water shocks the roots, while hard water leaves deposits in the potting mix and is not suitable for all plants. Prefer rainwater or filtered water, gentler for the plant, and at room temperature.

• Leaving water in the saucer : this standing water suffocates roots and encourages root rot. After watering, empty any excess after a few minutes.

• Watering too much in winter : during the cold season, growth slows and water uptake decreases.

• Wetting the foliage : pouring water over leaves, especially on sensitive species such as orchids or cacti, leads to spotting and disease. Always water at the base of the plant, directly onto the potting mix.

Practical tips for successful watering

Beyond frequency and quantity, some simple practices improve the comfort and vigour of houseplants:

• Adapt watering method : some species benefit from immersion, such as orchids. The pot is plunged for a few minutes in a basin so the rootball becomes thoroughly moist. Others prefer standard top watering.

• Use a long-spouted watering can : this allows water to be directed precisely at the base of the plant, without wetting the foliage.

• Check drainage regularly : ensure the pot’s drainage holes are not blocked and add a layer of clay pebbles or gravel if necessary. This prevents water stagnation.

• Lighten compost if needed : overly compact potting compost retains too much moisture. Mixing in some perlite or sand improves root aeration.

• Watch for signs from the plant : softened, yellowing or curled leaves often indicate a watering problem. Adjust watering at the first signs to correct quickly.

• Place plants according to their needs : situate tropical species in naturally humid rooms (kitchen, bathroom) and succulents in dry, bright spots to reduce watering errors.

• Maintain good ambient humidity : for plants that appreciate humidity (tropical plants, ferns…), mist foliage or place pots on a tray of moist clay pebbles.