Growing Garlic in Warmer Climates (Subtropical)
Almost all garlic (10 of the 11 garlic groups) are day length dependant for bulbing, which means that they won’t start bulbing until 12 hour day lengths start and then require continued suitable weather for the remaining 4-6 weeks of bulbing (< 35°C).
This is why the one garlic group called Subtropicals and the Elephant Garlic are very suited to the warm climate conditions, as they are day length neutral, which means they don’t need 12 hour day length to start bulbing and have a short growth cycle of only 5.5 – 6 months (compared to the 7-9 months growth cycle of temperate climate garlics).
Subtropicals including Glen Large, Southern Glen, Italian Pink and Italian Red are planted in late February to mid-March as this is the most moderate 5-6 month period throughout the year for garlic to grow well in warm climates.
Growing day length dependent Turbans, Artichokes, Creoles and Asiatics in warmer climates is possible, but are usually grown in the more elevated areas, or cooler regions where temperatures remain less than 35°C during their 6-7 month growth cycle and importantly for 4-6 weeks after 12 hour day length occurs, to trigger bulbing and allow them to finish bulbing.
The below weather chart for Brisbane has been annotated showing a Subtropical growth cycle and a day length dependant growth cycle (Turbans, Artichokes, Creoles and Asiatics) and illustrates the potentially hot weather of greater than 35°C that coincides with 12 hour day lengths that make growing these garlic challenging.
To help these garlic survive after 12 hour day lengths start, grow them in an area that is partially shaded in late afternoon sun or use a shade cloth to reduce the temperatures.