8 things to work on in your garden this autumn

Summer has been and gone, and we say hello to autumn, when the leaves begin to develop those signature tints. The start of the new season might have you wondering: ‘what jobs should I be looking to tick off at home?’

Gardening is a great place to start. Here’s what our friends from the Botanic Gardens of South Australia recommend for a season that some say is the most important of the year for your garden:

1. Plant, plant, plant

Autumn’s the ideal time of year to plant – particularly trees, shrubs and perennials – because air temperatures have cooled, soil is still warm and you’ve hopefully had some rainfall to increase soil moisture.

The first thing to do is consider the state of your soil and undertake any soil improvements required, such as mixing in organic matter like compost, worm castings or soil conditioners.

You may also want to include inorganic soil conditioners. For instance, adding gypsum if you have clay soils.

These adjustments will help make nutrients more available to plants, and improve aeration and how water is retained.

You may need to look at your soil’s pH levels too – you ideally want it to be between pH6-7.

When the soil’s warm and moist, new plantings will establish good root growth before slowing down in winter.

You’ll see benefits again in early spring, when the plants you planted in autumn have had time to establish and show wonderful new growth ahead of the next summer’s heat.

Autumn is the best time to begin transplanting shrubs or trees if they need to be moved from a shady or sunny spot, and it is also a great time to propagate new plants from cuttings.

Take 10 cm cuttings from hardwood herbs such as rosemary and bay, or natives such as banksias, grevillea and coastal rosemary.

Remove the lower leaves, dip cuttings into the appropriate hardwood hormone powder (or honey, if you prefer) and pot them in small containers of free-draining potting mix.

Keep the cuttings just moist and shelter them from the direct sun and out of the wind – you can use a plastic bag supported by wire. By spring, you should have rooted cuttings ready to pot up.

2. Plan your veggie garden

Start forward planning and planting now for your winter crops to ensure a bumper harvest.

There are lots of vegetables that can be planted in autumn. Try to get all brassicas, such as cabbage, kale, Asian greens, broccoli and cauliflower, in by the start of April.

Take a leaf out of the Botanic Gardens’ winter crop for the Little Sprouts Kitchen Garden, which includes beetroot, broad bean, broccoli, coriander, cabbage, celery, fennel, kohlrabi, lettuce, parsnip, snow and sugar snaps peas, silverbeet, swede, spring onion and turnip.

3. Fertilise

Choose a well-balanced fertiliser – one that has equal ratios of nitrogen, phosphorus and potassium, and contains calcium.

This will encourage plant cells to thicken, making your plants more resilient to fungus and disease during the cold and wet of winter.

The Botanic Gardens of South Australia use Neutrog Biological Fertilisers that are full of beneficial microbes that your soil and plants will love.

4. Look after your lawn

Autumn’s ideal to help your lawn recover from the hot and dry summer, and to prepare it for the wetter and colder months.

It’s a good time to fertilise your lawn, but ideally you want a lower nitrogen content fertiliser than what you use in spring and summer.

A more evenly balanced nitrogen, phosphorus and potassium fertiliser will help repair damaged areas by promoting new growth. It will also promote new root growth before soil temperatures drop, giving your lawn a head-start for next spring.

Remove fallen leaves from your lawn regularly as these will deprive the lawn of light, causing it to die off and create brown patches.

5. Focus on roses

For rose aficionados, early autumn’s the time to fertilise to ensure your roses have a good supply for that final specky autumn flush.

6. Attract worms

Earthworms are a sign your soil is fertile. When you add organic matter such as leaves and cow manure to your garden soil, you'll attract earthworms, so there's no need to add more to your garden.

The worms you’ve attracted with organic matter will add nutrients from their castings, and make tunnels.

7. Load up your leaves

This time of year produces a lot of leaf matter – why not use this to start a compost of leaves?

Traditionally, ‘oak leaf mould’ was an integral part of potting mixes, but more recently it has been replaced by ‘coir’, which comes from the husk of a coconut, or pulverized well-composted pine bark.

Other handy hints

Good garden hygiene is always a great idea. Take care around the base of shrubs and trees to limit the build-up of mulch and other garden matter around the stem or trunk region, particularly in high rainfall areas such as the Adelaide Hills. This helps prevent collar rot and other fungal attack.

Autumn is also an ideal time to get stuck into pruning your fruit trees – either to shape your trees or encourage more fruit production.

Pruning should be carried out on deciduous trees only when they are fully dormant – too early or too late can open the tree to fungal attack through the wound.

This season there will be downy and powdery mildews appearing, particularly in the Adelaide Hills. Get onto it now, either with a soft option like spraying it with milk or using a preparatory fungicide.

Just make sure to read the instructions well and check their impact on the environment. Some can contain harsh elements which can be damaging to sensitive ecosystems.

You might also like to trim your hedges before the onset of winter to keep them compact and bushy at ground-level.

This story was originally published on theBotanic Gardens of South Australia blog, and was originally published on Good Living in March 2017.

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