To irrigate or not

Posted: 26/03/2015 in Planting
How much water does a healthy garden need? In the run-up to summer, the season conventionally associated with thirsty plants and heavy watering, irrigation is a subject generating much heated debate among gardeners.

Water is lost from the soil through evaporation and run-off and is also transpired through the leaves of plants. Dry conditions during the summer aggravate water loss, which causes plant fail and a problematic garden just when you need it to be looking its loveliest.

The best defense, some advocates maintain, is to make sure your garden gets plenty of water through a rigged-up irrigation scheme – an automatic system, with timers and pop-up sprinklers, the works. You can go on an extended holiday out of the country and never worry about low soil moisture or wilting blooms.

Over-watering, however, is not only wasteful and unfashionable, it can kill plants through root rot or disease from waterlogged soil. Some gardeners aim for minimal irrigation – just enough water in the root zone, where plants draw water from the soil, to stay healthy.

This demands understanding soil type (loam holds water and drains well; clay absorbs slowly and is prone to run-off; sandy soil drains away water quickly) adding organic matter like compost to improve the soil, and mulch to prevent evaporation.

It also involves using efficient irrigation systems such as drip irrigation, which delivers water directly to the root zone at very low rates – one drop at a time, minimising run-off or evaporation.

But there are those who believe that irrigation can be done away with entirely by choosing plants that naturally adapt to the environment and climate. Plants grown in the appropriate conditions thrive with minimal care and can well get on with only rainfall for water.

It all has to do with learning all about your garden’s soils and micro-climates and choosing plants that can best adapt to them. For instance, moisture-loving plants should be placed where soil stays wet while those that can tolerate drought are best in areas where the soil is dry in the summer.

Native plants likewise won’t require irrigation. These are naturally-occurring species to the habitat or region that have survived and thrived without human assistance. They are particularly suited to difficult areas in your garden (for example, shade) and while often associated with wildlife gardens and ‘chaotic’ schemes, add interest and decorative flair while boosting the surrounding ecosystem.

To irrigate or not to irrigate? ‘Tis a question fraught with high-minded discussion among gardeners, we’re afraid. But from a practical perspective, the decision probably rests on the individual needs, capabilities and inclinations of the garden owner. One can also take a bit from each school of thought, by grouping plants by their water needs, combining native and non-native plants, and creating irrigation and non-irrigation zones.

Whatever works best, doing your gardener’s homework should be the first step in either direction. Knowing your garden environment and climate will help you decide how to be water-wise, and whether to irrigate or not.

To irrigate or not

comments powered by Disqus

To irrigate or not