August Vegetable and Herb Gardening Calendar for Subtropical Climate Australia

Australia - subtropical climate zones
Australia – Subtropical climate zones

It’s August, the weather is still cold and windy, but the end of winter draws near. Days begin to grow noticeably longer, and the change of season isn’t too far away.

The weather in Brisbane is mild, with the possibility of frosts and occasional storms, but much drier, while Sydney averages around 11 days of rain this month.

This month is the last chance to complete the pruning of deciduous trees and shrubs, and for planting raspberries and brambleberries (such as blackberries and their hybrids). It’s now also time to sow the first summer vegetable seeds. Where there’s a danger of frost, sow seeds in trays and place them in a protected area such as a veranda, greenhouse, or indoors near a sunny window.

Towards the end of August, feed fruit trees with organic fertiliser, manure and compost by digging these into the soil when preparing new garden beds. The soil organisms will begin breaking down the organic plant food to slowly release nutrients into the soil after a week or two, ready for the beginning of new spring growth in September. If fruit trees need a feed of potash (potassium), late autumn is also the time to do that too.

Things to Do This Month:

  • Continue planting deciduous trees, shrubs, vines and cane fruits (and roses!). Wait till spring to plant citrus.
  • Continue pruning deciduous fruit trees (not apricots, best to prune these in late autumn when the leaves start yellowing, during dry, preferably windy weather to prevent diseases entering the pruning cuts). To prune fruit trees, first cut away any dead or diseased wood, then cut away any branches growing inwards towards the centre or crossing other branches (to prevent rubbing and bark damage), and finally, prune tree to shape using the appropriate technique for that species.
  • Continue pruning deciduous shrubs (and roses too if you didn’t prune them in July).
  • Prune dead seed-heads, stems and branches on herbaceous perennial plants.
  • Relocate any deciduous plants (trees, shrubs, vines) or herbaceous perennial plants growing in the wrong place in winter. (Evergreens can only be moved in autumn and early spring, where they have time to regrow roots – remember, they retain leaves in winter which transpire and lose water).
  • Apply organic fertiliser to fruit trees, so that the slowly released nutrients will become available when the new growth commences in spring.
  • Spray peaches and nectarines to protect against leaf curl fungus. Use lime sulphur or a copper fungicide at the bud swell stage (just before the buds begin to open) but before pink bud stage or when flower colour shows. It is too late to spray once flowering occurs.
  • Feed pot grown shrubs and plants and refresh their potting mix by scraping off the top 2.5cm and replace it with fresh potting mix which has been mixed with slow-release fertiliser. Top dressing with compost is also beneficial.

Vegetables and Herbs to Grow in August (Subtropical Climate)

August Seeds to Sow and Seedlings to Plant
(Subtropical Climate Australia)
Sow/PlantHarvest (weeks)
Amaranthdst7-8
Angelicast18 months
Asparagus*plant crowns2-3 years
Asparagus Pead8-11
Basils10-12
Beans (Climbing)d9-11
Beans (Dwarf, Bush)d7-10
Beetrootdst7-10
Borages8-10
Burdockd17-18
Cabbagest8-15
Cape Gooseberryd14-16
Capsicums10-12
Carrotd12-18
Celeriacs14-28
Celerys17-18
Chillis9-11
Chinese Cabbagest8-10
Chivesdst7-11
Collard Greensd8-11
Coriander (Cilantro)dst30-45
Cowpeas (Black Eye Peas)d11-14
Cucumbers8-10
Daikond8-10
Dilldt8-12
Eggplants12-15
Fennel (Bronze)dst14-15
French Tarragons30-40 days
Globe Artichokesdst42-57
Horseradishplant crowns16-24
Jerusalem Artichokesplant tubers15-20
Kohlrabidt7-10
Leeksd15-18
Lemon Balms8-10
Lettucedst8-12
Luffas11-12
Marrows12-17
Mints8-12
Mustard Greensdst5-8
NZ Spinach (Warrigal Greens)s8-10
Okras11-14
Oniont25-34
Oreganod6-8
Parsnipd17-20
Peast9-11
Potatoplant seed potatoes15-20
Pumpkindst15-20
Radishd5-7
Rhubarbplant crowns12 months
Rocketd21-35 days
Rockmelon (Cantaloupe)s10-16
Rosellas21-25
Saged18 months
Salsifyd14-21
Silverbeet (Swiss Chard)dst7-12
Snow Peast12-14
Spinacht5-11
Spring Onions (Bunching Onions)dst6-10
Squashs7-8
Strawberry (plants)t11
Summer Savoryd6-10
Sunflowerd10-11
Sweet Corndst11-14
Thymes42-52
Tomatillos10-14
Tomatos8-17
Turnipd6-9
Watermelon*s9-14
Winter Savorys6-10
Yaconplant tubers25
Zucchini (Courgette, Marrow)s6-9

Key:
d = sow seeds directly into ground
s = sow seeds into seed tray
ds = sow seeds directly into ground or seed tray
t = transplant seedlings (small plants) into larger pots or plant into ground
*= frost tender
**= sow after frost

Download printable PDF version of Gardening Calendar (Australian Subtropical Climate) – August

To help improve these garden calendars, feedback and additional information from readers is greatly appreciated! Australia’s climate varies considerably, and local knowledge of when particular things need to be done in the garden are most helpful to others living in those area, so please feel free to share.

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