With forecasters predicting this summer’s El Nino weather pattern to be one of the top 3 or 4 driest on New Zealand’s record, what is the best way to water your garden?
Water more seldom but thoroughly
One to two watering sessions per week are usually sufficient: better to water more seldom but with plenty of water rather than a little water often.
Keep leaves dry
Water at the roots using a soaker hose, rather than shower setting if you have a sprayer – it’s the roots that need the water not the leaves. Wet leaves can become diseased leaves and leaves that are made wet in the sun can develop slight burn marks. Use the soaker setting for efficient watering at the root zone.
Water late in the evening or early in the morning
When you water in the evening, less water evaporates off the cooled soil and the plants can sufficiently supply themselves with water before the next day’s heat.
If you water in the morning and you do get moisture on the leaves, this gives them time to dry out. It's much more difficult for plant diseases to get a foothold when the foliage is dry.
Give the right water quantity
This means that the water must sufficiently reach the plant's roots. Low water quantities often only reach the top few centimetres of soil. Lawns and annuals concentrate their roots in the top 15cm / 6" of soil; for perennials, shrubs and trees, it is the top 30cm / 12". This means that in heavy clay soil, it may take hours for water to percolate down. Use your finger or a shovel to check the progress.
Water in stages
Water needs a moment to seep into the soil. To stop the water flowing away unused, it’s better to water repeatedly in stages.
Mulch reduces surface runoff and slows evaporation from the soil.