Begonia 'Passing Storm' (passing storm begonia) care

Light

Begonia 'Passing Storm' is what florists mean by "bright spot, no direct sun" — close enough to a south or east window to feel the brightness, with a sheer curtain or a few feet of distance keeping the sun off the leaves. Bright indirect light keeps the contrast and silver tones vivid. Direct sun bleaches and scorches the thin leaves, while low light makes growth pale, flat, and leggy. A phone lux-meter at the leaf surface should read 1,500-3,000 lux at noon.

Watering

Water begonia 'passing storm' when the top 2-3 cm of soil is dry, roughly every 5-7 days in growth. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water around the soil, keeping leaves and crown dry, and let the surface dry slightly between drinks. Rex begonias rot easily, so avoid soggy soil and cut watering right back during winter dormancy.

Soil and pot

Begonia 'Passing Storm' grows best in light, airy, free-draining mix. A fluffy peat- or coir-based mix with plenty of perlite and some bark suits the shallow roots. Avoid dense composts; Rex begonias need air around the rhizome to prevent rot. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Begonia 'Passing Storm' sits happiest at around 50-70% humidity and 18-24°C (64-75°F). Thrives in high humidity; dry air causes brown, crispy leaf edges and leaf drop. Use a pebble tray, humidifier, or grow case rather than misting, which can mark the leaves and invite mildew. If you keep the room above 18 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed begonia 'passing storm' sparingly. Feed every 3-4 weeks in spring and summer with a balanced liquid fertilizer at half strength. Stop feeding entirely when growth slows and the plant rests in autumn and winter. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on begonia 'passing storm' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Powdery mildew — Rex begonias are highly prone to it in still, humid air. Ensure good airflow, keep leaves dry, and remove affected foliage at the first white patches.
• Winter leaf loss — Many Rex begonias drop leaves and go semi-dormant in winter. Reduce watering and stop feeding; new growth resumes from the rhizome in spring.
• Crispy brown edges — Caused by low humidity or dry heat. Raise humidity with a tray or humidifier and keep the plant away from radiators and cold drafts.
• Rhizome rot — Overwatering or burying the rhizome leads to soft, mushy rot. Keep the rhizome at the surface and let the soil dry slightly between waterings.

Propagation

Propagate from leaf cuttings (whole-leaf or leaf-wedge) or rhizome sections placed on a moist, airy mix in a warm, humid propagator. New plantlets form at the cut veins over several weeks. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Begonia 'Passing Storm' is toxic to pets. The ASPCA lists Begonia as toxic to cats and dogs. Soluble calcium oxalates, most concentrated in the underground rhizome, cause vomiting and salivation if ingested, with kidney failure possible in grazing animals. Keep out of reach of pets. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Begonia 'Passing Storm' deep-dive guides

Every aspect of begonia 'passing storm' care, each with its own calibrated guide:

• Begonia 'Passing Storm' watering schedule
• Begonia 'Passing Storm' light requirements
• Best soil mix for begonia 'passing storm'
• Begonia 'Passing Storm' fertilizing guide
• When to repot begonia 'passing storm'
• How to propagate begonia 'passing storm'
• Begonia 'Passing Storm' growth rate & size
• Begonia 'Passing Storm' cold hardiness
• Begonia 'Passing Storm' temperature & humidity
• Is begonia 'passing storm' toxic to cats & dogs?
• Is begonia 'passing storm' toxic to cats?
• Is begonia 'passing storm' toxic to dogs?

Featured in these plant shortlists

Begonia 'Passing Storm' qualifies for 3 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
• Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
• Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

Related guides

Begonia 'Passing Storm' is also commonly called passing storm begonia or rex passing storm.

• Types of begonia — varieties identified, with care and pet-safety
• Snake plant care — light, water and common problems
• Dracaena care — light, water and common problems
• Peperomia care — light, water and common problems
• All 2464 plant care guides in the Growli library