Page 25 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

said that light levels halve every 50cm further from a window you are. This

means that for most tree species light levels are too low, even when stood on a
bright windowsill. It needs to be understood that glass filters out many of the UV
rays that plants require for the process of photosynthesis; many trees species can
fail to receive enough light on a south-facing windowsill even though the heat of
the sunlight is burning their leaves.
Trees that do not receive enough light will fail to grow strongly if at all. Any
growth that is produced will tend to have long internodes and become 'leggy'.
Leaves will be over-sized in an effort to catch maximum light.

Sageretia theezans/Chinese Bird Plum by Harry Harrington. Sageretia are a
tropical species that require protection from temperatures below +10ºC and are
grown indoors between September and April each year.
Some tropical species however are used to growing on the forest floor
(ficus/Serissa/Sageretia amongst others) in their natural habitat where there is
naturally little light and these will cope with lower light levels indoors.
Trees grown indoors should be placed on sunny windowsills and/or provided
with overhead fluorescent lamps. This should be sufficient for many tropical
species but will probably still be too dark for ordinary woody temperate species.
Ordinary fluorescent lamps or aquarium lights kept about 6 inches above the
tree for 12-16 hours a day can be used to supplement light levels.
Do not place trees on windowsills that are closed behind curtains at night, the
temperature in between the window and curtain can rapidly drop below room
temperature during the night.