After the heatwave

Well, first real summer day today and time for serious watering. Both Joe and Rosanne adore summer weather but now being the caretakers of thousands of plants, there is a definite downside – our plants do not have the same enthusiasm for this weather as we do except for a few sun lovers like figs, pomegranates and carob. However, those of you who have visited out gardens at the height of summer might have been surprised at how lush and green everything is. We don’t waste water but neither are we too parsimonious as our precious plants rely on us when they are thirsty in a climate where it often does not rain for weeks, even months. If you have spent good money on an interesting and exotic plant please don’t begrudge it a couple of dollars of extra water and then you get to savour a luscious mango or avocado.

I’ve probably said much of this last summer but it bears repeating as there are new followers on the page and lack of water is the gardeners’ constant lament in South Australia. So a few important points: firstly watch the weather forecast closely as these days it is nearly always accurate except that promised rain often doesn’t come. We all knew today would be close to 40 so give the plants a good soak the night before so there is moisture in the soil and they can transpire properly when the heat hits. Gardening advice in the media often says that a good soak once a week is better than a sprinkle every day. This may be true for trees and ornamentals but edible crops require often daily watering as the temperature rises. Especially vulnerable are newly planted seedlings and baby trees, especially citrus.

Also needing special care are plants in pots and the smaller the pot the more fussing over it needs. Wherever possible, move the pots to a shady spot if prolonged heatwave conditions are expected. They will survive a day or so if well watered but are much safer in the shade for the duration. The temperature in the pot is about 10 degrees higher than the ambient temperature, maybe even more in the ubiquitous black plastic pots everyone uses. Plant roots only survive to about 37 degrees so a potted plant is super stressed sitting out in the Adelaide sunshine when it gets much over 30. Daily watering is essential; I water twice a day when it’s close to 40.

Another group of plants that need extra care is, surprisingly, subtropicals. When I started gardening a few years ago I assumed that they would love the heat…they are tropical after all! Big mistake! The kind of heat they love is moist and somewhat oppressive to us humans. You know those days when the sky is grey, the air is sticky and it looks like it might rain any minute. In the tropics the temperature doesn’t go much over 32 so to expect a plant to flourish when it is baked by super dry Adelaide heat over 35 is just plain wishful thinking. You can grow out-of-climate plants but you need to create a microclimate which resembles where they come from, ie warm wet summers and cool, dry winters – the exact opposite of what we have here. So plenty of water on your bananas, mangos, avocados etc to give them a sporting chance of surviving summer, especially for the first couple of years. You might even like to construct a little tent around the plant with shadecloth which will also help prevent frost damage in the winter.

Strawberries are one plant that is very susceptible to wilting and toasting and need daily watering in hot weather. The picture shows some of my strawberry patch in mid-January last year directly after a long heat wave. Even I was astonished how well they survived with not a brown or wilted leaf in sight – little and often is the way to go with berry and vegetable crops.