All About Growing Warm-Season Herbs

For most of Australia (including Sydney), herbs can be divided into cool-season herbs and warm-season herbs based on their preferred planting time. For a low-maintenance summer herb garden in Sydney, a combination of Basil, Oregano, Thyme, Rosemary, and Lemongrass provides a wide range of culinary uses and grows well in warm weather. 

Types of Warm-Season Herbs

Herb	Flavor / Aroma	Common Uses
Basil	Sweet, peppery, slightly spicy	Pesto, pasta, pizza, salads
Oregano	Strong, earthy, peppery	Pizza, pasta sauces, Mediterranean dishes
Thyme	Earthy, savory, slightly minty	Soups, stews, roasted vegetables, meats
Rosemary	Pine-like, woody, aromatic	Roasted potatoes, lamb, chicken, breads
Sage	Warm, earthy, slightly peppery	Stuffing, poultry, sausages, butter sauces
Marjoram	Sweet, floral, mild oregano-like	Soups, vegetables, meat dishes
Lemongrass	Fresh lemon, citrusy	Thai curries, soups, stir-fries, tea
Bay Leaf	Mild, herbal, slightly floral	Stocks, soups, stews, braises
Vietnamese Mint	Spicy, minty, peppery	Vietnamese salads, noodle dishes
Summer Savory	Peppery, thyme-like	Beans, meats, soups
Greek Basil	Stronger and spicier than sweet basil	Mediterranean cooking, pesto
Thai Basil	Anise, licorice-like	Thai curries, stir-fries, noodle dishes

By Uses

Purpose	Recommended Herbs
Italian Cooking	Basil, Oregano, Marjoram, Thyme
Mediterranean Cooking	Rosemary, Oregano, Thyme, Bay Leaf
Asian Cooking	Lemongrass, Thai Basil, Vietnamese Mint
Roasted Meats	Rosemary, Sage, Thyme
Tea & Drinks	Lemongrass, Basil
Container Gardening	Basil, Thyme, Oregano, Rosemary

HOW TO GROW WARM_SEASON HERBS

Quick Beginner Tips

1. Plant in full sun and warm soil.
2. Start with basil—it is one of the easiest warm-season herbs.
3. Harvest often to keep plants productive.
4. Avoid overwatering; most herbs dislike soggy soil.
5. Grow in pots if garden space is limited.
6. Feed lightly—too much fertilizer reduces flavor.

1. Choose a Variety

Easy varieties for beginners

Rank	Herb	Difficulty
1	Basil (Genovese)	Very Easy
2	Lemongrass	Very Easy
3	Oregano	Very Easy
4	Thyme	Very Easy
5	Thai Basil	Easy

2. Growing Timeline

Month	Growth Stage	Tasks
September	Preparation	Choose sunny location, prepare well-drained soil, add compost, gather seeds or seedlings.
October	Sowing & Planting	Sow seeds or transplant seedlings after frost danger passes. Water regularly and apply mulch.
November	Seedling Establishment	Thin crowded seedlings, monitor moisture, protect from pests, begin light feeding.
December	Active Vegetative Growth	Plants grow rapidly. Pinch growing tips to encourage bushy growth. Continue watering and feeding.
January	Early Harvest Stage	Begin harvesting leaves regularly. Remove flower buds on basil types if growing for leaves.
February	Peak Production	Frequent harvesting, maintain watering, feed lightly every 4–6 weeks, check for pests and diseases.
March	Mature Plants	Continue harvesting, prune overgrown plants, divide lemongrass if needed.
April	Flowering & Seed Production	Allow selected plants to flower if saving seed. Pollinators visit flowers.
May	Late Season Harvest	Make final large harvests for drying or freezing.
June	End of Season	Collect seeds, remove spent annual herbs, take cuttings from perennial herbs if desired.

3. Growing Conditions

• Well-drained, fertile soil (6.0-7.5ph).
• 6–8+ hours full sun daily
• Spring to early summer planting (20–35°C)

4. Planting

Best Planting Time in Sydney

• Early Spring to Summer

0. Prepare soil:

Improve soil with compost or aged manure.

1. Planting Steps

Herb	Direct Sow	Start Indoors
Basil	Yes	4–6 weeks before planting
Thai Basil	Yes	Yes
Perilla	Yes	Yes
Summer Savory	Yes	Yes
Stevia	Better as seedlings	Yes
Lemongrass	Usually from divisions/stalks	Rarely

From Seeds or Seedlings

1. Choose a sunny location.
2. Sow seeds or transplant seedlings after frost risk passes.
3. Plant at recommended spacing.
4. Water thoroughly after planting.
5. Apply mulch to retain moisture and suppress weed
6. Spacing: 20–60 cm depending on herb

Herb	Plant Spacing	Row Spacing	Notes
Basil	25–30 cm	40–50 cm	Good airflow reduces disease.
Thai Basil	25–30 cm	40–50 cm	Similar spacing to sweet basil.
Oregano	30–45 cm	45–60 cm	Spreads outward as it grows.
Thyme	20–30 cm	30–45 cm	Compact, low-growing herb.
Sage	45–60 cm	60–90 cm	Becomes a large bush.
Rosemary	60–100 cm	90–120 cm	Large varieties need plenty of room.
Stevia	30–45 cm	45–60 cm	Benefits from good air circulation.
Perilla	30–45 cm	45–60 cm	Can become bushy and tall.
Summer Savory	20–25 cm	30–40 cm	Compact annual herb.
Lemongrass	60–100 cm	90–120 cm	Forms large clumps over time.

2. POT Planting

Best Varieties for Pots

• Genovese Basil
• Siam Queen Thai Basil
• Common Stevia
• English Thyme
• Greek Oregano

Pot Size Guide

Herb	Minimum Pot Size	Ideal Pot Size	Depth
Basil	20 cm (8 in)	25–30 cm (10–12 in)	20–25 cm
Thai Basil	20 cm	25–30 cm	20–25 cm
Oregano	20 cm	25–30 cm	20–25 cm
Thyme	15 cm	20–25 cm	15–20 cm
Sage	25 cm	30–40 cm	25–30 cm
Rosemary	30 cm	40–50 cm	30–40 cm
Stevia	20 cm	25–30 cm	20–25 cm
Perilla	25 cm	30 cm	25 cm
Summer Savory	15–20 cm	20–25 cm	20 cm
Lemongrass	30 cm	40–50 cm

5. Watering

Stage	Frequency
Newly planted	Keep soil consistently moist
Establishing plants	Water 2–3 times weekly
Mature plants	Water deeply when top 2–3 cm of soil dries
Container plants	Often daily during hot weather

Tips

• Water at the base of plants in the morning to reduce disease.

6. Supporting & Pruning

Support requirements depend on rootstock.

Supporting:

Herb	Support Needed?
Basil	No
Thai Basil	No
Summer Savory	No
Stevia	Sometimes if tall
Perilla	Usually no
Lemongrass	Rarely; divide large clumps if they flop

Pruning & Pinching:

Herb	Pruning Method
Basil	Pinch growing tips regularly
Thai Basil	Remove flower buds to extend leaf production
Stevia	Cut back by one-third during active growth
Perilla	Pinch tips to encourage bushiness
Lemongrass	Remove dead outer leaves
Summer Savory	Light trimming throughout season

General Rule

• Start harvesting when plants reach 15–20 cm tall.
• Never remove more than one-third of the plant at once.

7. Feeding

Time	Fertilizer
Before planting	Compost or aged manure
Every 4–6 weeks	Balanced organic fertilizer
Container plants	Liquid seaweed or fish emulsion every 2–4 weeks
Excessive feeding	Avoid; reduces flavor concentration

8. Pollination

Not required unless you want to collect seeds.

9. Common Problems

roblem	Symptoms	Solution
Aphids	Clusters of small insects	Spray with water or insecticidal soap
Whiteflies	Tiny white flying insects	Use yellow sticky traps
Spider Mites	Fine webbing, speckled leaves	Increase humidity and wash foliage
Powdery Mildew	White powder on leaves	Improve airflow and avoid overhead watering
Root Rot	Wilting despite wet soil	Improve drainage and reduce watering
Slugs & Snails	Holes in leaves	Hand-pick or use barriers
Heat Stress	Wilting during hot afternoons	Water deeply and mulch
Nutrient Deficiency	Pale growth	Apply balanced fertilizer

10. Harvesting

Herb	First Harvest
Basil	6–8 weeks after sowing
Thai Basil	6–8 weeks
Summer Savory	6–8 weeks
Perilla	8–10 weeks
Stevia	10–12 weeks
Lemongrass	4–6 months after planting

Harvest Tips

• Harvest in the morning after dew dries.
• Pick young leaves for best flavor.
• Regular harvesting encourages new growth.

11. Storage

Method	Storage Life
Refrigerated fresh herbs	3–10 days
Herb stems in water	1–2 weeks
Frozen chopped herbs	6–12 months
Dried leaves	6–12 months
Lemongrass frozen stalks	Up to 12 months

Best Storage Method

Herb	Best Method
Basil	Fresh or frozen
Thai Basil	Fresh or frozen
Perilla	Fresh
Summer Savory	Drying
Stevia	Drying
Lemongrass	Freeze stalks whole

(Source: chatGPT)