Glass Jar Garden

Plants

Pennywort as drawn in the simulator

Pennywort

Hydrocotyle tripartita

BeginnerFine in a closed jar

Clover-like leaves on running stems. Fills gaps fast.

What the simulation uses

Light
1,500 to 10,000 lux
The brightness it grows well in.
Humidity
60 to 100 % RH
Air moisture it is happy in; below the lower end it dries out.
Temperature
18 to 28 °C
Comfortable range; outside it growth slows.
Dies at
below 5 or above 33 °C
Days beyond these temperatures kill it.
Soil pH
6 to 7.5 pH
Soil acidity it prefers.
Grows up
0.5 cm/month
How fast it gains height in good conditions.
Spreads
2.75 cm/month
How fast its edge creeps outwards.
Copes with wet
good
How well it stands soggy soil; poor means rot comes quickly.
Copes with still air
good
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
0.09 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
3 %/month
Share of its leaves it sheds each month as litter for the cleanup crew.
Soft leaves
yes
Soft new growth that hungry isopods will nibble.
Full size
6.5 cm tall, 40 cm wide
Its size when grown, before the lid stops it.

Care

Day length
10 to 14 h
Substrate
Wet

What kills it

Description

This is the pennywort sold for terrariums and the front of aquariums. Its stems creep across wet, marshy ground and root wherever they touch. Keep the soil damp and trim it when it spreads too far.

Also called hydrocotyle, Hydrocotyle sp. 'Japan', marsh pennywort.

Estimated, where sources were thin: no species-level rates, light or temperature limits found; rot behaviour in a flooded sealed jar is assumed from the shallow crown.

Sources

Grow it in a jar