Help plants survive in full sunshine

Not all plants enjoy being bathed by the sun’s hot rays, writes Stephanie Choo

THOSE plants you have in your garden may not enjoy the bright sun and clear blue skies as much as you do. Potted ones and those that are not heat- or drought-tolerant can easily wilt and die during hotter-thanusual days. To help plants survive a period of hot weather better, you’ll need to keep them well-watered, well-rooted in soil rich in organic matters and in the shade, away from the harsh afternoon sun.

Water, composing of two hydrogen atoms and one oxygen atom, is the primary material that makes up a plant’s structure. In a drought, the plant will droop and wilt because when soil dries out, it ends up losing water and its turgor pressure decreases.

Absorbed through the roots from the soil, water that is drawn up into stems and leaves is released continuously to the atmosphere through transpiration evaporation of excess water from leaves in the form of water vapour.

When the air gets drier, the temperature goes up or air movement increases, and plants transpire far more water to cool themselves down as long as there’s water in the soil.

During and even before a heatwave or a period of hot weather, water plants deeply to ensure the whole root ball is moistened, and also more frequently. Instead of watering once a day as you’ll normally do, water twice instead.

Give the plant a good supply of water early in the morning before the heat hits and another time in the late afternoon to replenish water in the soil. This way the leaves will always have enough water to draw on from the roots.

Essentially, water is crucial for plants to carry on growing and surviving. The roots of plants can only absorb mineral nutrients from the water in the soil. In the process of photosynthesis, the atom hydrogen in water is used by plant to help build sugar and other molecules needed for growth.

USE RICH WELL-DRAINING SOIL

Organic matters such as ripened compost, peat moss and leaf mulch improve soil drainage and structure while adding nutrients. Mix them into the soil before planting.

The improved soil, when moist and squeezed in the hand, forms a hard ball but crumbles when forced between the fingers. To build and maintain the soil periodically, work in about 5cm layer of any organic matters or mulch into the soil.

Soil rich in organic matters is able to hold sufficient supply of moisture for plants to prevent them from wilting. Its friable consistency allows roots to form strongly and penetrate deeply so that the plant can keep going in a drought.

PROVIDE SHADE

The sun’s hot rays can be just too harsh during the midday hours. Too much sunlight can dry out and heat up the soil in a potted plant that is left in the open. Move the plant to a shady area to keep it cool and from wilting.

If not movable, place a piece of fabric to protect the plant from the sun. Plants such as annuals with shallow roots and new seedlings can benefit from some shade.