By: Justin Russell | June 28, 2017
It’s all well and good suggesting planting ideas for July, but have you ever actually measured the temperature of your soil during the dead of winter? In some areas, it will be warm. In others it will be moderate. In places like the highlands and southern Tassie, it’s likely to be colder than a dog’s nose. Only a few vegetables will germinate in such conditions, but before you write off this month as a planting free zone, try taking your soil’s temperature.
In the old pre-thermometer days, people would do the bare bum test. They’d drop their daks or hitch up their skirts and touch their bare bums to the soil to get a rough idea of its temperature. If it felt cold, they knew to wait a bit longer. If it felt comfortably warm, it was time to plant. Now I’m not suggesting you all start running around in the nick placing bare flesh against cold soil. Save those kind of shenanigans for summer. Instead, get yourself a soil thermometer (available in nurseries and online), poke it into the ground and use the temperature as a planting guide.
In very cold areas with a soil temp lower than about 15°C, the few things that can be planted from seed include broad beans, English spinach and onions. The soil is likely to be too cold for much else, except bare-rooted perennial crowns. Try rhubarb, horseradish, asparagus, globe artichoke and true shallots.
Warm temperate and arid/semi-arid areas usually have slightly warmer soil in July – as balmy as 20°C – and therefore more scope for planting. Try all of the above, plus shelling, sugarsnap and snow peas, radishes, turnips, swedes, broccoli, cabbage, cauliflower, kale, and Asian greens.
In the subtropics, an even wider range of plants can go in during July. It’s a good time to plant beetroot and silverbeet, carrots, salad greens, potatoes, bush and climbing beans, radishes, spring onions, leeks, Asian greens, parsley, Florence fennel, coriander, kale and peas.
Contrary to popular belief, it’s even possible to grow cool season vegies in a tropical winter. Use shade (and shadecloth) to provide slightly cooler air and soil temperatures, especially when growing non-fruiting plants such as leafy greens, lettuces and coriander, and above all, provide a regular supply of moisture during dry weather. In many cases the trigger that sends a plant bolting to seed is a sudden lack of water. Depending on your soil and aspect, you may need to water as often as every morning to keep plants well hydrated.
Other dry season planting ideas for the tropics are starch substitutes such as taro, cassava and cocoyam, and tubers including Jerusalem artichoke, Queensland arrowroot, galangal, yacon and turmeric. Plant these into well-prepared soil that’s kept just moist until wet season rains arrive. Don’t forget to sow successive crops of sweetcorn, zucchini, beans, carrots and beetroot.