---
title: Rex begonia in a terrarium | Glass Jar Garden
description: Rex begonia (miniature cultivars) (Begonia Rex Cultorum Group): Painted, metallic leaves. Needs humid air but rots in wet soil. Needs light 5,000 to 20,000...
url: https://glassjar.garden/guide/plants/begonia-rex-mini/
---

Plants

# Rex begonia (miniature cultivars)
Begonia Rex Cultorum Group

Moderate · Closed jar only

Painted, metallic leaves. Needs humid air but rots in wet soil.

## What the simulation uses

- Light: 5,000 to 20,000 lux (The brightness it grows well in.)

- Humidity: 75 to 95 % RH (Air moisture it is happy in; below the lower end it dries out.)

- Temperature: 16 to 26 °C (Comfortable range; outside it growth slows.)

- Dies at: below 7 or above 32 °C (Days beyond these temperatures kill it.)

- Soil pH: 5.5 to 6.5 pH (Soil acidity it prefers.)

- Grows up: 1 cm/month (How fast it gains height in good conditions.)

- Spreads: 1.25 cm/month (How fast its edge creeps outwards.)

- Copes with wet: fair (How well it stands soggy soil; poor means rot comes quickly.)

- Copes with still air: fair (Sealed jars have still air; poor means grey mould finds it.)

- Copes with shade: good (How well it holds on in dim light.)

- Copes with drying: poor (How well it survives the jar drying out.)

- Water use: 0.06 ml/cm²/day (Water drawn up from its roots per cm² of leaves in room air; a sealed jar cuts this to a fraction and returns it down the glass.)

- Leaf drop: 2 %/month (Share of its leaves it sheds each month as litter for the cleanup crew.)

- Soft leaves: no (Soft new growth that hungry isopods will nibble.)

- Full size: 17.5 cm tall, 22.5 cm wide (Its size when grown, before the lid stops it.)

## Care

- Day length: 10 to 14 h

- Substrate: Moist

## What kills it

- waterlogged substrate (Pythium root and stem rot)
- humidity below ~60%
- Botrytis on wet leaves
- direct sun scorch

## Description
Grown for its leaves rather than flowers, this begonia wants air above 75 percent humidity and makes a fine closed-jar plant. The catch is rot. If the soil stays wet, roots and stems give way, so use a mix that drains well.

Also called painted-leaf begonia, mini rex begonia.

Estimated, where sources were thin: light_lux (Wikipedia gives 1500-2200 fc for greenhouse; lowered for terrarium LEDs); temp_c; growth rates; mini cultivar sizes.

## Sources

- [plants.ces.ncsu.edu/plants/begonia](https://plants.ces.ncsu.edu/plants/begonia/)
- [en.wikipedia.org/wiki/Begonia_rex](https://en.wikipedia.org/wiki/Begonia_rex)

[Grow it in a jar](https://glassjar.garden/?guide=plants/begonia-rex-mini)

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