Light first: match the plant to your window

Before you worry about watering schedules or fancy misters, work out where the light actually falls in your home. Almost every houseplant problem traces back to light, and the gap between a bright windowsill and the corner two metres away is enormous. A south-facing window gives strong, direct sun for much of the day. An east window offers gentle morning light. A west window is bright but hotter in the afternoon. A north window is cool and dim, and a hallway with no window at all is a plant hospital waiting to happen.

As a rough guide, cacti, succulents and rubber plants want that sunny south spot. Snake plants, ZZ plants and pothos will cope a metre or two back from a window. Calatheas, ferns and peace lilies prefer bright but indirect light — think filtered through a sheer curtain rather than baking in full sun. If a plant is stretching, with long gaps between leaves and pale new growth leaning towards the glass, it is asking for more light. Move it closer.

Watering without guesswork

Forget the cupful-a-week rule. Water when the compost tells you it is ready, not when the calendar says so. Push a finger into the compost up to your second knuckle, roughly 3cm. If it feels damp, wait. If it feels dry at that depth, water properly — slowly, until water runs out of the drainage holes at the bottom.

Then, and this matters, tip away whatever collects in the saucer after ten or fifteen minutes. A plant left sitting in standing water is the single most common way beginners lose a houseplant. Roots need air as well as moisture, and permanently soggy compost starves them of it.

• Summer: most plants need a drink every five to ten days.
• Winter: growth slows and light fades, so many plants need water every two to three weeks or less.
• Always: use room-temperature water. Cold water straight from the tap shocks tropical roots.

Plants differ, too. Snake plants and ZZ plants would rather dry out completely between waterings. Ferns and calatheas prefer compost that stays lightly damp, but never sodden.

Why yellow leaves usually mean too much moisture

If a lower leaf turns yellow, goes soft and slightly limp before dropping off, overwatering is the likely culprit. When compost stays wet for days, roots suffocate and start to rot. Unable to take up nutrients, the plant sacrifices its oldest leaves first, so the yellowing begins at the bottom and works upwards.

Contrast that with underwatering: leaves go brown, crisp and dry at the edges, often curling inwards. If the yellow leaf is pale and the compost is bone dry, your plant is thirsty, not drowning.

What to do if you suspect overwatering:

• Stop watering and let the compost dry out to about 3cm deep.
• Check the drainage — are the holes blocked, or is a hidden plastic pot sitting inside a decorative one?
• Move the plant somewhere brighter and airier so it uses water faster.
• If the roots are brown and smell sour, take the plant out, trim the rotten roots with clean scissors, and repot into fresh compost.

Humidity, warmth and the quirks of British homes

Most tropical houseplants come from places where humidity sits at 60 per cent or more. Central heating in a British winter can drop a room to 30 per cent, which is why ferns, calatheas and peace lilies develop brown, crispy leaf tips. Group plants together so they share the moisture they release, stand pots on a tray of pebbles with water kept below the pebble line, or move humidity-lovers into the bathroom if it has a window.

Temperature matters just as much. Keep plants away from radiators, draughty doorways and single-glazed windowsills where overnight temperatures can plummet. Most houseplants are happiest between 18°C and 24°C — roughly the same range you are.

Choosing plants that suit your space

• North-facing or dim corners: snake plant, ZZ plant, pothos (devil's ivy), spider plant.
• Bright, indirect light: peace lily, philodendron, rubber plant, most ferns.
• Sunny south or west windowsills: cacti, succulents, jade plant, and herbs such as rosemary and thyme.
• Bathrooms with a window: Boston fern, calathea, nerve plant.

Start with three or four tough plants rather than a dozen fussy ones. Confidence grows much faster that way.

A simple weekly routine

Once a week, take five minutes. Check the compost of each plant with your finger. Rotate pots a quarter turn so growth stays even. Look at the undersides of leaves for pests — small sticky patches or fine webbing mean trouble, and a wipe with a damp cloth usually sorts early problems before they spread.

Feed with a diluted liquid fertiliser every two to four weeks through spring and summer, then stop entirely from October to February. Repot in spring, and only when roots appear through the drainage holes. If you are short on space, a plant stand or a shelf by the window lets you grow upwards rather than outwards.

Above all, do not panic about perfection. Yellow leaves happen, and they are information rather than failure. Learn to read them, and your plants will tell you exactly what they need.