How to Grow Basil in Australia

When should I plant Basil in Australia?

Plant basil in spring once the danger of frost has passed and the soil has warmed up. Basil seeds germinate best when soil temperatures are at least 18°C, ideally 20°C to 25°C. This tender herb thrives in warm conditions and will struggle if planted too early in cool soil.

Planting times by climate zone

These zones are broad groupings, so let your local frost dates decide the exact timing.

Timing tips

• Soil temperature: 18°C to 25°C for reliable germination
• Frost consideration: Plant at least 2 weeks after the last frost; basil is frost tender
• Succession planting: Sow every 4 weeks for continuous fresh leaves all summer
• Christmas harvest: Plant by late October in temperate zones (early November in Melbourne) for holiday picking

What soil does Basil need?

Basil grows best in light, fertile, and well-draining soil with a pH between 6.0 and 7.5. Good drainage is critical to prevent root rot, which basil is particularly susceptible to, especially in cooler or wetter conditions.

Soil preparation checklist

• Soil type: Light, loamy, and well-draining soil
• pH range: 6.0 to 7.5, slightly acidic to neutral; add lime if soil is too acidic
• Organic matter: Mix in generous amounts of compost or well-rotted manure
• Drainage: Critical for root health; does not tolerate waterlogged soil
• Soil preparation: Dig over to 20cm depth, remove weeds, and incorporate organic matter
• Container mix: Use premium quality potting mix with added compost

Improving your soil

For heavy clay soils, build raised beds or mix in generous amounts of coarse sand and compost to improve drainage. In sandy soils, add plenty of compost or aged manure to increase water and nutrient retention. A top dressing of worm castings at planting time gives seedlings an excellent organic boost.

How often should I water Basil?

Water basil regularly to keep the soil consistently moist but never soggy. Basil has shallow roots and can wilt quickly if the soil dries out, yet it is equally damaged by overwatering and poor drainage.

Watering guidelines

• Seedlings: Water gently with a fine spray daily to keep surface moist
• Established plants: Water deeply 2-3 times per week, depending on weather
• Flowering: Maintain consistent moisture; water stress can cause early flowering (bolting)
• Hot weather (35°C+): Water daily in the morning, may need a second light watering in extreme heat
• Best time to water: Early morning so leaves dry before night, reducing disease risk

Signs of water stress

• Underwatering: Leaves wilt, become limp, and may turn yellow or brown at edges
• Overwatering: Lower leaves turn yellow and drop; stems may become soft and black at base (root rot)

Water-saving tips

• Apply a 5-7cm layer of straw or sugar cane mulch to retain soil moisture
• Drip irrigation or soaker hoses are ideal for delivering water to roots without wetting leaves
• Water at the base of the plant, not over the foliage
• Suitable for water-wise gardens if mulched well and watered efficiently

Water-wise rating: 3 out of 5. Requires regular moisture but can be managed efficiently with good practices.

How do I feed Basil?

Feed basil with a balanced liquid fertiliser every 3-4 weeks during the active growing season. Basil is a moderate feeder that responds well to nitrogen for lush leaf growth but avoid over-fertilising which can dilute flavour.

Feeding schedule

• Before planting: Incorporate 5-10cm of compost or aged manure into the soil
• At planting: Mix a handful of worm castings or blood and bone into each planting hole
• First feed: 3-4 weeks after planting or when plants are 15cm tall
• Ongoing feeding: Apply a complete liquid fertiliser (fish emulsion or a balanced liquid feed) every 3 to 4 weeks; seaweed solution is a tonic rather than a feed, so use it alongside fertiliser, not instead of it
• Flowering: Pinch off flower buds to direct energy into leaf production; no special feed needed

Organic fertiliser options

• Compost tea: Apply every 2 weeks as a gentle, nutrient-rich soil drench
• Worm castings: Side dress plants monthly with a handful per plant
• Seaweed solution: Use fortnightly to promote strong growth and stress resistance
• Blood and bone: Apply once at planting and again mid-season for slow-release nitrogen
• Pelletised chicken manure: Apply lightly (small handful per square metre) at planting time

Signs of nutrient deficiency

• Nitrogen deficiency: Older leaves turn pale green or yellow; growth is stunted. Solution: Apply a nitrogen-rich feed like fish emulsion.
• Potassium deficiency: Leaf edges turn brown and crispy. Solution: Apply sulphate of potash or a potassium-rich organic fertiliser; go easy on wood ash, which raises soil pH.
• Other common deficiencies: Magnesium deficiency shows as yellowing between leaf veins. Solution: Apply Epsom salts (magnesium sulphate) as a foliar spray.

Protecting Basil from extreme weather

Basil is a heat-loving but tender herb that needs protection from frost, extreme sun, and strong winds in Australian gardens. With simple strategies, you can extend your harvest season significantly.

Heat protection (35°C and above)

• Use 30-50% shade cloth during the hottest part of the day to prevent leaf scorch
• Mulch with 7cm of straw to keep roots cool and conserve moisture
• Water deeply in the morning; potted plants may need watering twice daily
• Position to receive morning sun and afternoon shade in very hot climates

Frost protection

• Cover with frost cloth, hessian, or an old sheet on cold nights
• Grow in pots that can be moved to a sheltered verandah or indoors overnight
• Avoid watering foliage before a predicted frost
• Plants blackened by frost will not recover; replant in spring

Wind protection

• Plant near a fence, wall, or taller plants (like tomatoes) to provide a windbreak
• Stake taller varieties if they become leggy
• Best planted in a sheltered but sunny part of the garden

Heavy rain and humidity

• Ensure excellent drainage; consider planting in raised beds in high rainfall areas
• Space plants 25-30cm apart to maximise air circulation and reduce fungal disease
• Water at the base of plants to keep leaves dry
• Raised beds are highly beneficial in areas with high summer rainfall

Pests and disease solutions for Basil

Basil can face these common challenges in Australian gardens. All solutions below are suitable for organic growing.

Common pests

• Snails and slugs:
  • Identification: Irregular holes chewed in leaves, silvery slime trails
  • Damage: Can decimate young seedlings overnight
  • Organic control: Hand pick at night, use beer traps, or apply iron-based snail bait
  • Prevention: Clear garden debris, use crushed eggshell or diatomaceous earth barriers
• Aphids:
  • Identification: Small green, black, or white insects clustered on new growth
  • Damage: Suck sap, causing distorted growth and spreading viruses
  • Organic control: Spray with soapy water or horticultural oil; blast off with water
  • Prevention: Encourage ladybirds and lacewings; avoid over-fertilising with nitrogen
• Whitefly:
  • Identification: Tiny white flies that swarm when plant is disturbed
  • Organic control: Use yellow sticky traps; spray the undersides of leaves with a horticultural oil or potassium soap spray registered for whitefly on vegetables and herbs, and follow the label

Common diseases

• Fusarium wilt:
  • Cause: The fungus Fusarium oxysporum f. sp. basilici, carried in soil and on seed, and recorded in Australia
  • Symptoms: Sudden wilting, brown streaks inside stems, plant collapse
  • Organic treatment: No cure; remove and destroy affected plants
  • Prevention: Plant resistant varieties; practise crop rotation; ensure good drainage
• Downy mildew:
  • Cause: Peronospora belbahrii, a water mould (an oomycete, not a true fungus) first found in Australia in 2017. It is favoured by humid, still conditions and leaves that stay wet overnight.
  • Symptoms: Yellow patches on upper leaves, greyish-purple fuzzy growth underneath
  • Organic treatment: Remove affected leaves at the first sign and pull badly affected plants; sprays give little control once it has taken hold
  • Prevention: Space plants well, water at the base in the morning so leaves dry quickly, harvest often to keep the canopy open, and do not save seed from infected plants

Australian-specific challenges

• Possums: They love basil! Protect with netting or a wire cloche, especially overnight.
• Birds: May peck at seedlings; use netting or bird scare devices.
• Grasshoppers and katydids: Can chew large holes; hand pick or use exclusion netting.

Integrated pest management tips

• Plant flowering herbs like dill and coriander nearby to attract predatory insects
• Do not plant basil in the same spot more than once every 3 years
• Plant with tomatoes and garlic, which can deter some pests
• Inspect plants weekly, especially under leaves, for early signs of trouble

What grows well with Basil?

Basil grows well beside tomatoes and capsicums, which enjoy the same warm, well-fed, regularly watered conditions. Companion planting can improve the health and flavour of your basil while creating a more resilient garden ecosystem.

Best companions

• Tomatoes: The traditional Italian pairing; both like the same warm, well-fed conditions, and the taller tomato gives basil a little afternoon shade.
• Capsicums and chillies: Share basil's love of warmth and regular water, so they are easy to manage in the same bed.
• Oregano: Acts as a living mulch, suppressing weeds and creating a beneficial microclimate.
• Lettuce: Basil provides light shade for lettuce in hot weather, delaying bolting.
• Beans: Basil and beans grow happily side by side and do not compete heavily for nutrients.

Australian native companions

• Lemon myrtle: Its summer flowers feed hoverflies and other beneficial insects that also patrol your basil.
• Prostrate grevilleas: Provide ground cover that helps retain soil moisture.

Plants to avoid

Keep Basil away from these plants:

• Rue: Traditionally said to hinder basil, so keep the two apart.
• Common sage: Can inhibit basil growth when planted very close together.
• Cucumber: Some gardeners report basil can slow cucumber growth, though evidence is mixed.

How do I know when Basil is ready to harvest?

Basil is ready to harvest when plants are 15-20cm tall and have developed several sets of true leaves. You can begin harvesting as soon as the plant is well-established, typically 6 to 10 weeks after sowing. Regular harvesting promotes a bushier, more productive plant.

Harvest signs

• Visual signs: Lush, full plants with vibrant green leaves (colour varies by variety)
• Touch test: Leaves are tender but firm, not tough or leathery
• Size: Harvest leaves when they are medium-sized, before they become overly large and potentially bitter
• Timing: Best flavour is just before the plant flowers; pinch off flower buds as they appear

Harvesting tips

• Best time of day: Morning after dew has dried for maximum flavour and essential oil content
• Harvest method: Pinch or cut stems just above a leaf pair, which encourages two new branches to form
• Tools needed: Clean fingers or sharp scissors/secateurs
• Frequency: Harvest lightly but regularly; never remove more than one-third of the plant at once

Storage methods

• Fresh storage: Store stems in a glass of water on the bench for 3-5 days, like a bouquet
• Refrigeration: Wrap leaves loosely in a slightly damp paper towel and place in a plastic bag in the crisper for up to 1 week
• Freezing: Chop leaves, pack into ice cube trays, cover with water or olive oil, and freeze. Store cubes in a bag for 6 months.
• Drying: Hang small bunches upside down in a warm, dark, well-ventilated place. Crumble and store in an airtight jar for 1 year.
• Preserving: Make into pesto and freeze, or infuse into vinegar. For basil oil, read the note on basil oil further down first.

Seed saving

Allow a few stems to flower and go to seed. Once flower spikes turn brown and dry, cut them off and place in a paper bag. Shake to release the tiny black seeds. Store in a cool, dry place. Note that different basil varieties can cross-pollinate if grown close together.

How to use Basil in the kitchen

Basil is prized in the kitchen for its vibrant, peppery, and slightly sweet flavour with hints of anise and clove. Its fresh aroma and bright taste are the soul of many Mediterranean and Asian dishes.

Flavour profile

Sweet Genovese basil has a classic, robust flavour that suits pesto and tomato sauces. Thai basil offers a sharper, more liquorice-like note ideal for curries and stir-fries. Lemon and lime basil varieties add a citrus twist. Heat mellows the flavour, so add fresh basil at the end of cooking.

Preparation tips

• Washing: Swish gently in a bowl of cold water to remove grit; pat dry with a tea towel or use a salad spinner
• Cutting: Tear leaves by hand to prevent bruising and blackening that occurs with a knife (chiffonade by rolling leaves and slicing thinly if preferred)
• When to add: Add fresh basil in the last few minutes of cooking to preserve its delicate flavour and bright colour

Cooking methods

• Raw: The best way to enjoy its full flavour. Lovely in salads, on bruschetta and as a garnish
• Sautéed: Add at the very end to warm through and release aroma
• Roasted: Not typical, but can be used in roast vegetable medleys
• Steamed: Add to fish or vegetables in the last minute of steaming
• Grilled: Brush whole sprigs with oil and grill briefly as a garnish

Flavour pairings

• Proteins: Chicken, lamb, white fish, prawns, mozzarella cheese, eggs
• Vegetables: Tomato, eggplant, zucchini, capsicum, garlic, onion
• Herbs and spices: Garlic, oregano, parsley, chilli, lemon zest
• Dairy: Parmesan, feta, ricotta, buffalo mozzarella, cream
• Oils and acids: Extra virgin olive oil, balsamic vinegar, lemon juice

Cuisine styles

Basil features prominently in:

• Italian: The star of pesto Genovese, Caprese salad, and Margherita pizza
• Thai: Essential in green and red curries, pad kra pao (a holy basil stir-fry) and Thai basil chicken
• Vietnamese: Used fresh in pho and fresh spring rolls

A note on basil oil

• Infused oils: Never steep fresh leaves in oil for weeks, as fresh basil kept under oil is a botulism risk. If you make basil oil, warm clean, dry leaves gently in the oil, strain them out, keep the oil in the fridge at 5°C or below and use it within a week, or freeze it in small portions. For longer keeping, use dried basil.

Organic growing tips for Basil

• Plant health: Pinch out the growing tip when plants are 15cm tall to encourage bushy growth. Regularly remove flower buds to prolong leaf production.
• Soil building: After harvesting, plant a green manure crop or add compost to replenish the bed.
• Biodiversity: Interplant with marigolds and nasturtiums to attract beneficial insects and confuse pests.

Frequently asked questions

Grow your own Basil

Ready to start growing? Browse our Basil seeds:

• Sweet Genovese Basil Seeds: the classic Italian pesto basil
• Thai Basil Seeds: aromatic, with purple stems and flower heads, essential for Asian cooking
• Lemon Basil Seeds: bright citrus flavour for salads and seafood