How to Care for Begonias Indoors

Begonias are one of the most rewarding houseplant families you can grow — painted rex foliage, polka-dotted angel wings, waxy everbloomers — and one of the most misunderstood. Most begonia disasters come down to two mistakes: treating them like a fern (too wet) or like a succulent (too dry). This guide covers what begonias actually want, and how care shifts slightly between the main types.

First, know which begonia you have

• Cane begonias (like the polka-dot Begonia maculata) grow tall, bamboo-like stems with swollen nodes. Easiest indoors.
• Rex begonias are grown for spectacular painted leaves — silver, purple, near-black. The fussiest about humidity.
• Rhizomatous begonias creep from a thick surface rhizome and tolerate lower light better than the others.
• Wax begonias (semperflorens) are the compact bedding classics that also live happily on a bright windowsill.
• Tuberous begonias are the showy summer-flowering type; they die back and need a winter rest, so treat them as seasonal.

Light

Bright, indirect light is the sweet spot for every begonia: within a metre of an east-facing window, or set back from a south- or west-facing one behind a sheer curtain. Direct midday sun scorches the thin leaves and fades rex colours; deep shade produces leggy stems and small, dull foliage. Rhizomatous types cope best with a dimmer corner, and in winter almost all begonias appreciate being moved closer to the glass.

Watering: the part everyone gets wrong

Water when the top 2–3 cm of soil feels dry — for most homes that's roughly every 5–7 days in summer and every 10–14 days in winter. Begonias have fine, shallow roots that rot quickly in soggy soil, but they also sulk hard if the root ball dries out completely. Water at the soil line, not over the leaves, and always empty the saucer after ten minutes. If in doubt, wait a day: a slightly thirsty begonia recovers, a rotted one usually doesn't.

Humidity — yes; misting — no

Begonias love 50–70% humidity, and rex types visibly crisp up below that. But this is the one humidity-loving plant you should never mist: water sitting on begonia leaves is an open invitation to powdery mildew and botrytis. Raise humidity around the plant instead — a pebble tray, a small humidifier, or grouping plants together — and keep air gently moving.

Warning: if you see a white, dusty film on the leaves, that's powdery mildew. Isolate the plant, remove the worst leaves, improve airflow, and treat early — it spreads fast between begonias.

Soil, pots, and feeding

Use a light, airy mix: standard houseplant compost cut with a generous third of perlite. Begonias like being slightly snug in their pots, and a too-large pot holds water their shallow roots can't use — go up only one size when roots circle the base. Feed with a balanced liquid fertiliser at half strength every two weeks from spring to early autumn, then stop for winter.

Pruning and propagation

Pinch the growing tips of cane and wax begonias every few weeks in spring and summer to keep them full instead of lanky, and deadhead spent flowers. Propagation is a joy: cane cuttings root in a glass of water in two to four weeks, and rex begonias will even sprout plantlets from a single leaf laid on moist mix with a few cuts across the veins.

Common begonia problems

• Yellowing lower leaves: almost always overwatering — check drainage and let the top layer dry out.
• Crispy brown leaf edges: air too dry or the root ball dried right out.
• White dusty patches: powdery mildew — act immediately, improve airflow, stop wetting the foliage.
• Leggy, stretched growth: not enough light; move it brighter and pinch it back.
• Sudden leaf drop in autumn: usually a cold draught or a radiator blasting nearby — begonias like a steady 16–24°C.

Tip: not sure which begonia you own? Snap a photo in PlantMe — the app identifies the species and variety in seconds and sets watering reminders matched to it.