Water wise gardening
Are you doing your bit in your garden to conserve water?
When is the best time to water?
Early morning is the best time to water the garden, as it allows plants sufficient water to get through the heat of the day. When water is applied in the middle of the day, much is lost through evaporation.
How much water?
In dry conditions, it is best to water plants and soil thoroughly, or not at all. If only the top couple of centimetres or so of the ground are dampened, plants will develop roots in this shallow layer where they are even more vulnerable to the drying effects of the sun. Try to moisten the soil to a depth of at least 30cm. Roots will then be encouraged to grow downwards, into a layer of soil that is insulated from the sun and will consequently remain damp for much longer.
Know when to water:
To know when an area requires watering takes practise. Factors such as the temperature, soil and time of day will influence this. And thus the best test is always the finger test – feel the soil to a depth of a few centimetres. Sometimes the soil surface looks dry, but it may still be moist enough further down. You can also use a bamboo stick or a thin piece of wire to test the same way – if there is moist soil sitting on the stick when you remove it from the soil, you know it’s not yet time to water.
Deep watering vs. frequent shallow watering:
More water less often is better than frequent shallow watering because it encourages the plants to develop a deeper root system. Roots that remain close to the surface easily dry out when there is no water.
Second hand water:
Use recycled bath and washing water on lawns and gardens. Bath water may have to be siphoned out of a window or taken out by bucket. Diversion valves are available from plumbing suppliers to direct water from the washing machine out into the garden. As some washing powders and laundry detergents contain high levels of phosphorus and boron, select a product that is low in these ingredient. Alternatively just direct the final rinsing water onto the garden. Use the water in different areas to avoid any build-up of salts in the soil and alternate with tap water.
Terracing to trap rain:
Water gathers speed as it travels downhill, scouring land and eroding topsoil, but it does less damage if terracing slows down its headlong rush. Keep in mind that water is absorbed more readily in a level garden than in one situated on a slope.
Improving the soil structure:
A quick-draining, sandy soil retains little moisture and needs more water than clay. Incorporating compost, mulching and using water retaining products will increase the water holding capacity of your soil.
Mulch to retain moisture:
A thick layer of mulch over all bare soil and around plants (including trees) will retain soil moisture. Apply mulch while soil is moist (for example, after heavy rain or watering). Cover beds and borders with a rich organic mulch, at least 10cm thick. Such material, as well as being of benefit to plants and soil, is water retentive.
Size of the lawn:
Reduce the size of your lawn – replace it with hardy ground covers or hard landscaping (brick paving, cobbles, pavers or gravel chips).
Let the lawn look after itself:
In times of drought mow your lawn with the mover blades set high, or do not mow it at all. The more grass left on the lawn, the longer it will take to turn yellow. The grass will quickly go green again after the first rains.
Choose the right plants:
Hot dry areas are often considered difficult to plant and yet there are many beautiful indigenous South African plants that have evolved to grow in these conditions. You can also grow plants from around the world which come from desert or other places where water is scarce. In fact, it is possible to plant a successful dry garden which is never watered except by whatever rain falls upon it. A few examples:
Succulents:
Succulents (including cacti) are equipped to deal with lack of water, storing whatever is available in swollen leaves, stems or roots to use during drought.
Their dramatic and often bizarre shapes and textures make them exciting garden plants!
Just think of the eyecatching colours of all the different Vygies available.
Yuccas, agaves, aloes or portulacarias cast sculptural silhouettes against solid walls or sky.
And Crassulas, Echeverias, euphorbias, kalanchoes and sedums look stunning in between rocks and stones.
Indigenous S.A. plants:
A wide range of South African plants are naturally drought resistant. When planning your garden, start with plants you know are endemic (occur naturally) to your rainfall area. These will need minimal watering once established as they are perfectly adapted to your local climate.
Look out for these characteristics when selecting plants:
Succulent leaves: Bulbine spp.
Small leaves: Many Buchus (Agathosma spp.), Confetti bush (Coleonema spp.), and Felicias.
Hairy leaves: Arctotis spp.
Foliage colour: blue-green or grey: Gazania, Helichrysum
Fleshy root system: Agapanthus spp.
Deep, strong root system: Plumbago auriculata
Companion planting:
You can safe water by grouping plants according to their water needs. When planning your garden, grade all plants if possible according to how thirsty they are.
Strong, healthy plants:
Keep in mind that healthy plants tolerate periods of dryness better than weak and sappy plants which receive to much nitrogen. Try to use organic fertilisers.
Windbreaks:
Make use of windbreaks – cutting out drying winds will reduce water loss.
Casting cool shade:
Trees and taller shrubs cast pools of shadow which provide relief from summer heat, help to reduce evaporation and shelter smaller plants.
Sweet thorn (Acacia karroo) grows in any soil and climate and adapted to dry conditions.
Paperbark thorn (Acacia sieberiana var. woodii) develops a flat-topped crown which casts dappled shade, allowing other plants to grow beneath its canopy.
Wild olive (Olea europaea subsp. africana) is an evergreen tree , also adapted to dry conditions.
