Protecting Young Plants

Once your plants are growing out in the garden. their growth may still be checked by the cold air and soil early on in the season. Moreover, there's always the
HUH—MISSING?

Angling garden beds toward the sun not only increases the incident light; it also speeds up the spring rise in soil temperature. As a general rule, any strategy that increases the amount of sunlight falling on the plants or the soil will be beneficial.

Looking at the wider garden, the main negative influence on the warmth of your beds in the spring will be shade and wind. Depending on the sun's apparent path in springtime and early summer, you could either remove the shade elements or re-arrange the growing area.

If trees are the shading features, a knowledge of the daily and seasonal patterns of light and shade will allow you to cull or trim the minimum number. As far as wind is concerned, cloching offers good local protection, while windbreaks protect the garden as a whole. A cheap, temporary means of diverting the wind is to make piles of brushwood along the rows of plants.

Too much heat

The effects of too much heat on plants mostly concern water.

When the rates of both evaporation from the soil and transpiration from the leaves are greatly increased, plants wilt. The obvious solution is to provide shade. In some climates, gardeners supplement this by building massive walls of mud brick or similar heat-storing material. These walls can absorb some of the daytime heat and re-radiate it during the night, thus moderating the 24-hour extremes.

In addition, such walls can be used to support frameworks for shadecloths, screens, or vines. Trees not only provide shade; they also act as windbreaks and as coolers—they generate a cooling effect as water evaporates from their leaves.

You should try to optimize your use of shade—although in hot, humid climates there is a danger of fungal infections if the shade restricts air circulation. On the whole, wind is a form of energy that most gardeners could do without. It brings unwanted cold or heat, dries 'the ground, carries salt and dust, buffets plants, and scatters cloches.

Observe the pattern and direction of winds. In sheltered, inland areas wind may be of little consequence, but in mountainous and coastal regions it may dominate everything. Any physical barrier can act as a windbreak, but on the whole it is better to deflect or merely slow the wind than attempt to stop it.

Solid barriers, such as walls and fences set perpendicular to the wind, cause eddies on the lee side. As a rule, artificial windbreaks should always be porous. Trees and shrubs make the best windbreaks, but may take a while to be effective. If you live in a windy area with some established, well-placed trees (even if they are not what you really wanted or cause other difficulties), think carefully before removing them.

Designing for early warmth

Landscaping

One method of deflectinq the wind involves landscaping a windbreak on the windward side of the garden.

First shift some soil to build an earthwork; then plant trees on its leeward side. Select trees with varying heights at maturity—short at the top of the earthwork, tall at the bottom—so that the top of the windbreak is flat.

Profile planting

An A-shaped windbreak created from trees of varying height has two aerodynamic advantages: the slope on the windward side protects the windbreak from damage, and the slope on the leeward side keeps turbulence to a minimum.

Windbreak dimensions

The length of a windbreak such as a hedge should be at least 11 times its mature height. This is because the wind will sneak around the ends and generate eddies. As a rule, a windbreak will give protection some 10 to 15 times its height.

A tree windbreak needs to be long enough and high enough to achieve its purpose (see ***). It is usually several rows deep, with a roughly triangular cross-section. Ideally, you should choose trees that have other purposes, such as providing edible fruit or altering the level of the water table, but usually there will have to be some compromise between these and the effectiveness as a windbreak and the speed of establishment.

A serious conflict may arise between the need for a windbreak and the need for light when the sun is low. This can occur in high latitudes; it depends on the direction of the prevailing winds. In climates where you need protection against hot, drying winds the shading from trees is a bonus.

Wind

A row of trees act as the first line of defence against the wind. These protect a row of shrubs, which provide a semi-porous wind barrier for the garden beyond.
Many tree species grow more vigorously when coppiced or pollarded. Harvesting provides material for fuel, fencing, basketry, or general garden purposes.