Bonsai: Growing Conditions for Development

Soil

While the physical properties of the soil provide a secure anchorage for a tree, it is the soil’s chemical composition (itself linked to the physical structure) which enables the tree to develop and grow.

First and foremost, the roots draw water from the ground, vital to the process of photosynthesis already de-scribed. This water also contains essential mineral salts in dissolved form. These are sure to include nitrates, phosphates, potassium, calcium, magnesium and sulphur, as well as a number of metallic elements (or trace elements) like copper, zinc, boron, iron, manganese, molybdenum, etc. These mineral salts are transported to all parts of the plant by the sap.

The mineral salt requirement varies from plant to plant; this means that the nature of the soil governs the natural vegetation of a particular region. Where trees are grown in containers (bonsai trays or trees in tubs), the potting compost chosen should be adapted to the needs of the tree.

Exposure to light

As we have already seen, light is indispensable to the process of photosynthesis, without which the plant cannot develop. Exposure to light is often confused with exposure to sunlight, which is not the same thing at all. Some plants which require a great deal of light may suffer from prolonged exposure to the sun, whose hot rays may cause rapid dehydration of the plant.

All trees need light, but the amount and length of time may vary. In nature, a tree may ‘choose’ its exposure to light, to the extent that only plants exposed to a certain intensity of light will thrive. In bonsai cultivation, a choice must be made: whether to opt for one species rather than another to suit the location (for example, balcony or patio) or to select the exposure to suit the needs of the plant as in larger areas such as gardens, large terraces or balconies with different aspects.

Before you buy a bonsai tree, you must always find out the degree of exposure to light it requires.

Exposure to wind

growing conditions for bonsiaThis is important to the development of a tree in its natural surroundings, but less likely to affect artificially cultivated plants, particularly bonsai, which grow only in a strictly controlled indoor environment not subject to windy conditions. At the same time, one should not overlook the fact that wind may accentuate the ambient conditions. For example, a bonsai exposed to the sun will be more prone to dehydration if it is exposed to wind at the same time. By the same token wind increases the risk of frost in cold conditions.

Generally speaking, a bonsai should not be grown in a windy place, such as the edge of a balcony or terrace. Draughts should also be avoided, as these prejudice normal plant development. Of course, where bonsai are grown outside, their containers must be firmly anchored, so that they cannot be dislodged by a gust of wind.

Where bonsai are put on window or balcony ledges, the trays must be secured with steel wire. In some cases, the plants may have to be anchored or braced, which will also prevent them being forced out of shape by prevailing winds.

Climate

This mainly denotes the ambient conditions and in particular, the temperature and humidity (moisture taken in by the roots and present in the air). It goes without saying that the growth of any tree is directly linked to the climatic conditions. Everyone knows that tropical vegetation differs vastly from that of a temperate or cold climate.

A climate which is clement for most of the year, allows most species to grow. In some cases, human intervention may be needed, to water plants, for example, or protect them from frost, but most species can be grown in the soil outdoors without much difficulty. In bonsai, this applies to all species that come from cold, mountainous or temperate regions. Bonsai trees can and should live outdoors, provided the climatic conditions are not too harsh. In general this means where the temperature does not usually drop below – 5°C (23°F). If it does (or just before), the bonsai should be moved indoors during the cold weather, or into a well-lit room, where the temperature never exceeds 10°C (50°F). If the atmosphere becomes warmer and the level of humidity drops very low, the plant is likely to die. A horticultural maximum-minimum thermometer is available which can be placed near your bonsai.

Only some types of tree from the tropics need to be or will tolerate being grown indoors at a high temperature, above 15°C (60°F). Provided the atmosphere is humid enough, the plant is watered frequently and the leaves are frequently misted with water, these tropical trees should survive.

These ‘indoor’ bonsai can almost be considered as house plants. Some of them are simply ordinary indoor plants treated as bonsai – plants like azaleas, fuchsias, and so on.

Some genuinely tropical plants can also be grown under glass and treated, shaped and trained like bonsai. This applies to some bamboos, which can produce some very interesting effects. The distinctive elegance of the date palm {Phoenix dactylifera) which grows as a house plant to a height of 3 m (10 ft) or more but can be reduced to about 30 cm (1 ft), is also worth mentioning.

23. February 2012 by Dave Pinkney
Categories: Bonsai | Tags: , , , | Comments Off on Bonsai: Growing Conditions for Development

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