August is late winter across most of Australia, and one of the best months to start a summer herb garden from seed. Sow warm-season herbs such as basil undercover while it is still cold. Sow hardy herbs such as coriander, parsley and chives direct in milder zones, then harden everything off before the heat arrives. A small sowing now can set up a productive herb patch, with basil carrying the heat and coriander doing its best work earlier.
The aim is not to sow every herb you own in one heroic afternoon. Start a few sensible trays, label them properly, and give the heat-lovers somewhere warm. Future you will appreciate it when the first tomato sandwich needs basil, and the supermarket herbs look tired before they reach the checkout.
There is a quiet satisfaction in sowing herbs while the mornings are still cold. The garden looks bare, the kettle is on, and yet this is exactly when a summer of basil, coriander and parsley quietly begins.
Most herbs pay little attention to the calendar and a great deal to the weather. The trick is to match each one to your climate zone and give it a warm, sheltered start. Do that, and you move into summer with herbs that are already finding their feet, rather than tender seedlings you are trying to establish in the heat.
Why start your summer herbs in August?
August gives warm-season herbs the weeks they need to become sturdy seedlings before summer. In southern Australia it is late winter, so the aim is a head start undercover, not a rush outdoors. In the tropical north it is the dry season, a comfortable window before the wet build-up.
The real benefit is timing. Herbs started now can be ready to plant out once the soil warms and the last frost has passed, which is when they grow fastest. Starting from seed also costs little, and it often gives you varieties that many shop punnets do not offer.
Warm-season herbs to start undercover now
Basil is the herb to start undercover, because it resents cold and can sulk or rot if sown into chilly ground. Sow it in trays on a warm windowsill, in a glasshouse, or on a heat mat, and keep it out of cold draughts. A bright spot above the kitchen bench is often warm enough.
Other heat-lovers worth starting now include perilla and tulsi, also called sacred basil, both warm-season and aromatic, with perilla popular in Korean and Japanese cooking. Keep them snug and do not be in a hurry to move them outside. Basil planted out too early may grow slowly and can struggle to catch up, so patience now often pays off later.
Cool-tolerant herbs you can sow now
Many herbs are perfectly happy sown in August, and several prefer the cooler end of the season. Coriander is the classic example, since it can bolt quickly once the heat and longer days arrive. A late winter sowing buys you a good run of leaf first.
Good cool-tolerant herbs to sow now include:
- Coriander, parsley and chervil, which enjoy mild conditions.
- Chives and dill, easy, quick and forgiving.
- Oregano, thyme and sage, slower Mediterranean perennials best started in trays in mild gardens, or held until the soil warms in cold districts.
In frost-prone gardens, sow these into trays or a sheltered bed, and protect them on the coldest nights.
Your herbs, zone by zone
Timing shifts with your climate, so read your own garden alongside the calendar. The notes below cover the main zones, including Perth and southern WA. If you garden where frost lingers, check the Bureau of Meteorology frost potential maps and your local forecast before planting tender herbs out.
- Tropical (Darwin, Cairns, Townsville): the dry season suits many herbs now, and basil can often go straight into the ground while southern gardeners are still nursing trays. Give a little afternoon shade as it warms.
- Subtropical (Brisbane, Sunshine Coast, Coffs Harbour): sow hardy herbs direct, and start basil in trays or a warm sheltered spot.
- Arid and semi-arid (Alice Springs, Mildura, Broken Hill): start undercover against cold nights, and use a wetting agent on water-repellent soils.
- Temperate (Sydney, Melbourne, Canberra): start basil undercover, and sow hardy herbs direct in milder pockets.
- Mediterranean (Perth, southern WA, Adelaide): this is a good window while winter rain still leaves the soil workable. Rake a fine seedbed now, before summer turns the calendar into a watering roster.
- Cool and alpine (Tasmanian highlands, Orange, Stanthorpe): keep everything protected, and in these districts basil is often a September or October sowing, with trays kept indoors until then.
Giving August-sown herbs a strong start
Healthy soil and gentle handling do most of the work. Sow into a free-draining mix and keep it just moist, not wet. If the tray smells fresh and earthy, you are close. If it looks shiny and boggy, back away from the watering can.
Give seedlings as much light as you can, so they do not stretch and go leggy. A bright north-facing windowsill or the best spot on the back verandah does the job. Turn trays every few days if seedlings start leaning like they are trying to escape.
Go easy on feeding. Most culinary herbs taste better when they grow steadily, not lush and watery. A weak seaweed drink now and then is plenty for seedlings, especially if the mix is fresh. Before planting out, harden seedlings off over a week or so. Move them outside a little longer each day, to a sheltered spot near the back door. The gradual change keeps the weather from checking their growth.
A simple August herb plan
Small batches are the trick. A few neat rows are easy to water, protect and use. A dozen overexcited trays can turn into a leafy guilt trip by September
If you would like a plan to follow, this short sequence keeps things easy. It avoids a bench full of trays you cannot keep up with:
- Start basil undercover in trays on a warm sill or heat mat.
- Sow coriander, parsley, chives and dill into trays or a sheltered bed.
- Label everything, since young herb seedlings look much alike.
- Keep the mix just moist and the light bright.
- Harden off and plant out once the frosts have finished.
A little and often beats one big sowing, and you can browse our herb seeds to fill any gaps in the patch.
A heat mat can also help basil in a cold August, as our guide to using a seedling heat mat explains. Start a few trays now and you give yourself the best possible head start. By the time the first summer tomatoes are ripe, a pot of basil sits within arm's reach of the barbecue. That feels like a fair reward for a cold morning's work.
Frequently asked questions
Is August too early to sow basil outside?
In most of Australia, yes. Basil needs warm soil and resents cold, so start it undercover in August. Plant it out once the frosts have passed and the soil has warmed. In the subtropics and tropics you have more freedom to sow earlier.
Which herbs can I sow straight into the garden in August?
In milder zones, coriander, parsley, chives, dill and chervil are all happy sown direct now. In frost-prone gardens, sow them into trays or a sheltered bed and protect them on cold nights.
Do I need a heat mat or glasshouse?
Not essential, but they help. A warm windowsill above the kitchen bench will start many herbs. A heat mat or glasshouse simply makes warm-season herbs like basil faster and more reliable in a cold month.
Should I feed herb seedlings often?
Go gently. Over-feeding can reduce the essential oils that give herbs their flavour, so a weak seaweed solution occasionally is enough. Good soil and bright light matter more than heavy feeding.
How do I keep coriander from bolting?
Sow it now while the weather is still cool, pick the outer leaves regularly, and keep the water up as it warms. Coriander naturally runs to seed in heat, so a late winter sowing gives you the longest leafy run.
What if I only have a balcony?
Herbs are ideal for pots and balconies. Use a free-draining mix, choose a sunny spot, and keep a few small pots of basil, parsley and chives within easy reach of the kitchen.
Related growing guides
- Succession planting: how to harvest continuously, not all at once
- What to grow in winter: cool-season vegetables across Australia
- When the heat sets in: vegetables that thrive in an Australian summer
Ready to plant? Browse our Herb Seeds.