Page 60 - Tài liệu cây cảnh Bonsai4me Bonsai Basics

health in the roots and tree and root rot.

Varying Soil Mixtures To Suit Different Tree Species
Though all Bonsai require free-draining, water-retentive soils, different
species vary in their requirements for water and nutrients and this should be
reflected in their soil composition. Pines and Junipers for instance require less
water than most other species; this in turn means that they require a less water
retentive soil mix. Alternatively, flowering and fruiting species have increased
water requirements and tend to be planted in soil mixes with relatively high
water retaining capacities. When mixing your own soil, the ratio of water-
retaining material to drainage materials is varied according to the tree that it is
intended for. Very often grit is used to provide additional drainage to a bonsai
soil. By increasing the ratio of grit to the mix, the soil becomes increasingly free-

draining; by increasing the amount of water-retentive material, the greater its
water-holding capacity becomes.
Organic or Inorganic Soils
Soil mixes are described as being either organic or inorganic. Dead plant
matter such as peat or leaf-litter or bark are described as being organic soil
components. Inorganic soil mixes contain little to no organic matter; instead,
they are made up of specially-formulated soils such as volcanic lava, calcined
(baked) or fired clays. These materials are more difficult to locate than organic

materials, but can be found in garden centres, bonsai nurseries, and in the case of
some fired clays, supermarkets and hardware stores.
Organic Soil Mixes and Components
In past decades, Western bonsai enthusiasts tended to use organic soil mixes,
using a large proportion of peat, bark and leaf-litter mixed with grit to aid with
drainage. As time passed, our knowledge and understanding of bonsai in the
West increased, it is now acknowledged by most enthusiasts that organic soil
components such as peat are not conducive to the good health and vigour of a
tree. Peat and other organic soil components have many disadvantages; they can
be too water retentive, leading to the soil being continually sodden, particularly
during periods of rain in Autumn, Winter and Spring. Conversely, during periods

of high temperatures, dry peat can be difficult to thoroughly water, leaving dry
spots inside the rootball of the bonsai. Possibly the most serious problem with
organic soils is that although they may consist of appropriate sized particles
when the bonsai is first planted, they continue to break down in a bonsai pot and
become compacted. As the soil compacts it becomes airless and drains poorly.
Such waterlogged and airless soils soon suffocate the roots and can lead to
rotting roots and ill-health in a bonsai. The only organic component that I would