Last weekend, Auckland's soil temperature was over 27C. Soil temperatures will remain warm well into autumn, so there are plenty of growing opportunities to be had. To give you an idea of ideal plant growing temperatures, 15C is the soil temperature in spring when many plants start actively growing and seedlings are usually planted. Therefore, we should have reasonable time to get autumn crops going before the cold hits and the days are markedly shorter.
In cooler areas, cloches can extend the growing season. Just ensure they are open for ventilation during the day. To keep an eye on soil temperatures in your area, regions are listed in the weather section of the Weekend Herald.
The time for sowing winter seeds in punnets, and planting seedlings for winter vegetables, is now. We can also extend summer's growing season by planting quick mesclun salad crops, and continuing to harvest and water tomatoes, zucchinis and cucumbers to ensure more fruit come on.
This is a great time to use diluted liquid fertilisers such as comfrey tea or vermiliquid (worm tea) to keep your veges happy and to encourage fruiting.
Autumn is a prime time for fungal issues. In bad cases, it's better to pull out the affected plant then prepare the ground for winter crops.
Remember to water soil, not foliage. For white powdery mildew or end-rot on zucchinis and scallopini, this is particularly important. Avoid overcrowding plants, and ensure they get good airflow.
Spray foliage in the cooler part of the day with a "compost tea"; the compost's existing beneficial fungi and bacteria will then help to out-compete the problem fungi. Use healthy, home-made compost or vermicast and run water through it so it is well-diluted.
Or, spray with 1 teaspoon of baking soda, some milk and a drop of eco-detergent mixed with 1.5 litres of water. The change in pH on the leaf surface helps discourage fungus. At the University of Adelaide a solution of 1-10 milk to water has been proven to to control powdery mildew in vineyards.