To beat the heat this summer try a south facing garden bed. Normally a north facing garden will produce the Best results however once December is here, it's hard to keep everything alive. Most gardeners will refrain from growing most things over the Xmas period and will wait for the cooler Feb and march to arrive.
To grow lettuce, rocket and other greens, create a garden bed that faces south. Backing on to a hedge will provide extra protection from the sun and provide a home for beneficial bugs and animals to hide in.
Keep pots in your garden and arrange them create a little retreat for frogs. Frogs, toads are great pest control and you are lucky if you have them in your garden. As they drink through their skin, a bird bath or similar container laying on the ground will help attack these snail eaters into your garden.
Rocket and other greens will come to seed very quickly. To extend the life of your greens simply remove the sprouting flower stem. This is easily identified by the sprouting shoot protruding from it's centre.
Good luck and water regularly.