Have you ever wondered why your home-picked roses drop their petals earlier than ones from the florist? Well okay, the florist ones have extender crystals added to the water, but they have also been grown with the optimum plant food for long-lasting roses. Early petal drop or lack of flowers are all signs your plant needs more tucker, and water too. Poor fruit set is another sign that fertlising is needed. We had an ancient plum tree that gave perhaps two fruit a year. I assumed it was just too old too fruit. Then we built a chook run next to it. Result: flush after flush of new growth, and many sweet plums, at least in years with rain.

Another way to tell if your plant is metaphorically yelling 'I'm hungry' is to look at the leaves. If the oldest leaves are yellow but the young ones still green, your plant probably has a nitrogen deficiency. If all the leaves are yellow and gently falling you either have a fabulous display of autumn leaves or your plant is dying. If in doubt, twist a twig. An autumn leafer's twigs stay supple. If the twig gives a sharp, dry snap it's dead as a dodo.

This is also the time of year when your broccoli, cabbages and caulies may well be suffering lack of molybdenum. If the oldest leaves are longer and narrower than the new leaves, and the cabbage fails to heart or the broccoli or caulis give only small heads, add mixed trace elements to the soil according to directions on the packet, or spray the leaves a few times each winter with seaweed spray. Foliar feeding i.e. leaves not soil, is an excellent boost for winter cropping plants.

Are any of the plants in your garden leaning in one direction? They may be trying to get more sunlight. Prune above and around them, if possible, to give them a chance.

Basically, if the leaves look limp and unhappy, there is something wrong. Autumn leaves usually look quite perky till they drop off the tree. Look for small sap sucking pests, like scale. (Scrape off with an old tooth brush or use an oil spray). If newly planted, if may be a species that won't survive Canberra frosts. Check, quickly: you may still be able to save it by wrapping it in bubble wrap or even blankets at night.

Trees that suddenly quadruple in size and look lusher than a tropical rainforest in the monsoon may have found a crack in your water or sewage pipes. Roots rarely cause leaks - they just take advantage of them, then make them bigger, not to mention full of roots.

If your soil is hard and smells slightly sour, or had an excellent crop of sheep sorrel, it's compacted: add mulch, and then more mulch once that has half broken down, and scatter plant food on top of the mulch to help the process.

There is an old story about a farmer who'd lost his eyesight. His son drove the horse and cart so his dad could inspect the land they were planning to buy. ''Just tie the horse up to the biggest thistle,'' said the farmer.

''None big enough, dad.''

''Then we may as well go home.''

There's really no such thing as green thumbs. A friend rejoiced today that after many years of sitting there gloomily, her garden is suddenly blooming, fruiting, looking glorious. All it needed was some attention i.e. the past couple of months she's had time at home to get out into the sunlight, to feed and water and mulch.

The best way to have a flourishing garden is to have a small mooch around it at least once a week. Take a cup of coffee, enjoy the sunlight, and if you see a downcast plant, work out what's wrong. Ninety-nine point nine nine nine nine nine per cent of garden problems are easily solved. Just ask a gardener, a real life one, a newspaper or magazine one, or even online.

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