Plants
Rex begonia (miniature cultivars)
Begonia Rex Cultorum Group
ModerateClosed 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.