Warming air and longer daylight hours mean the garden is waking up. September is the season of maximum growth and it's the perfect time to spread fertiliser, this being when your plants most benefit from it.
If you maintain a compost heap and limit yourself to plants suited to your soil and climate, you may not need much extra fertiliser. But not everyone has time to make and spread compost, and all plants, when packed tightly into a flower bed, benefit hugely from extra nutrition.
Start with lime. Many NSW gardens have quite acid soil, technically below neutral (7 on the pH scale, sometimes as low as 4 to 5) so appreciate extra lime. Now is a good time to spread it, before new growth covers the ground. Follow directions for quantity on the bag.
Lime lasts for up to a year. Dolomite, that does a similar job but costs slightly more, lasts for three. If your soil is alkaline vegies will love it but if you long to grow acid-loving camellias and azaleas you'll need to acidify it by adding sulphur. You'll need more if your soil tends towards clay rather than sand.
Next, decide what type of all-purpose fertiliser to use. I prefer low phosphate fertilisers, because I have native Australian plants like correas, grevilleas and lomandras dotted around the garden among my exotics and many of them are allergic to extra phosphate.
I use organic fertilisers because the plants absorb their nutrients only as they need them. They're never in danger of over-stuffing themselves, which can occur with chemical fertilisers and may cause all sorts of damage.
Plants can drink but not eat. Liquid organic fertilisers are available from garden centres, or you can make your own from weeds and lawn clippings, or from dried manure (see The Land, July 2 and September 3).
Liquid fertilisers applied from a watering are quicker acting than dried pelleted manure or blood and bone, which need to be watered in, but they are slower to apply.
Lime, sulphur and fertilisers will all work their way down through the ground without any help from you. They don't need to penetrate deeply - a plant's feeding roots are near the surface, its deeper roots are for anchorage.
Plants' nutrition requirements differ and greedy feeders like peonies, and heavily pruned subjects like roses, benefit from extra fertiliser.
In addition to spring fertilising, you may like to give plants an extra feed before they set flowers: fertilise winter-blooming hellebores in late summer. Lastly, a surface mulch of hay or compost breaks down into humus. This retains the soil moisture that enables the fertiliser to reach plants' roots.