The Gravenstein apple tree is showing a yellow mottling on its leaves. Luckily for me the December issue of Gardening Australia has an article on secondary and trace elements with a chart to diagnose the problem. It looks like a calcium deficiency - the instruction is "if the ph is below 6.5 add dolomite limestone (calcium and magnesium).
Buninyong garden's soil is acidic at about a ph of 5.5 - 6, so dolomite has been added, but due to the acid soil, it is harder for trace elements to be taken up by all the veges and trees, so I'll make a foliar spray concentrate, and then dilute to spray the leaves of fruit trees, citrus and my green leaf vegetable broccoli (also good for cauliflower, cabbage, and silverbeet). When the tomatoes are bigger they can benefit too, (also use for well growing pumpkin, sweetcorn, and zucchini plants).
FOLIAR FEED RECIPE
The concentrate:
3 teaspoons of zinc sulphate (or a mineral mix containing zinc)
3 teaspoons of magnesium sulphate (also called Epsom salts)
1 cup (250ml) of fish emulsion (eg Charlie carp)
1 cup (250ml) of seaweed concentrate (eg Seasol)
mix into 10 litres (2.6 gallons) of water (= one Aussie watering can full)
Dilute to use:
1 part concentrate to at least 10 parts of water, eg. 1/2 litre of concentrate to 5 litres of water or more.
I have Epsom salts, Charlie carp and Seasol, but its off to the shop to buy some zinc sulphate.