Nasturtiums have bright, cheerful flowers and edible leaves with a peppery kick. Native to South America, they were introduced to Europe in the 1500s by Spanish explorers and quickly caught on as both ornamental and edible plants. In Australia, they self-sow happily in veg beds, thriving with little care and bringing vibrant life to the garden.
Sowing Calendar
Best Months to Plant – Nasturtium
Climate Zone
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Cool/Mountain
✓
✓
✓
✓
Temperate
✓
✓
✓
✓
Arid
✓
✓
✓
✓
✓
✓
✓
Subtropical
✓
✓
✓
✓
✓
✓
✓
Tropical
✓
✓
✓
✓
✓
✓
✓
✓
Cool/Mountain – Nasturtium
Method
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Start in trays
✓
✓
✓
✓
Plant out transplants
✓
✓
✓
✓
Direct sow
✓
✓
✓
✓
Temperate – Nasturtium
Method
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Start in trays
✓
✓
✓
✓
Plant out transplants
✓
✓
✓
✓
Direct sow
✓
✓
✓
✓
Arid – Nasturtium
Method
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Start in trays
✓
✓
✓
✓
✓
✓
✓
Plant out transplants
✓
✓
✓
✓
✓
✓
✓
Direct sow
✓
✓
✓
✓
✓
✓
✓
Subtropical – Nasturtium
Method
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Start in trays
✓
✓
✓
✓
✓
✓
✓
Plant out transplants
✓
✓
✓
✓
✓
✓
✓
Direct sow
✓
✓
✓
✓
✓
✓
✓
Tropical – Nasturtium
Method
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Start in trays
✓
✓
✓
✓
✓
✓
✓
✓
Plant out transplants
✓
✓
✓
✓
✓
✓
✓
✓
Direct sow
✓
✓
✓
✓
✓
✓
✓
✓
Where to Plant
In-Ground Garden Beds
In-Ground Garden Beds
• Traditional garden beds dug directly into the soil
• Suitable for deep-rooted crops and long-term plantings
• Offers natural soil ecology and drainage benefits
• Requires proper soil preparation and weed management
Shady Spots & Herb Gardens
Shady Spots & Herb Gardens
• Areas receiving dappled or indirect sunlight, often near trees or buildings
• Best for shade-tolerant herbs like mint, parsley, or greens like spinach
• Helps prevent sun stress and conserves moisture
• Often used in cooler corners of the garden
Raised Garden Beds
Raised Garden Beds
• Enclosed garden beds elevated above ground level
• Offer excellent drainage and warmer soil conditions
• Reduce bending and make gardening easier for mobility-restricted gardeners
• Ideal for most vegetables, flowers, and herbs
Pre-treatment
Scarification
• Gently rub the seed coat with sandpaper or nick it with a blade
• Aim to just break the outer shell without damaging the inside
• Soak scarified seeds in water for a few hours before sowing
• Common for hard-coated seeds like nasturtium or sweet pea
Soaking in Water
• Place seeds in a cup of clean, room-temperature water
• Soak for 8–24 hours depending on seed type
• Plant immediately after soaking to prevent rot
• Useful for large or hard seeds like beans and beetroot
Sowing Method
Start in Trays
• Fill seed trays or punnets with quality seed-raising mix
• Sow seeds at the correct depth—refer to seed packet for guidance
• Place trays in a warm, sheltered location with good light
• Mist or bottom-water to avoid disturbing small seeds
• Transplant seedlings once they develop 2–4 true leaves
Direct Sow
• Sow seeds directly into prepared garden soil or outdoor containers
• Best for plants that dislike transplanting, such as root vegetables and beans
• Loosen soil and remove weeds before sowing
• Sow at the recommended depth and spacing, then water gently
• Keep the area moist until germination and thin seedlings if needed
Watering
Medium
• Benefits from regular watering, especially during active growth or flowering
• Soil should remain moist but not soggy—allow topsoil to dry slightly between waterings
• Ideal for most vegetables, herbs, and flowering annuals
• More frequent watering may be needed during hot or windy weather
• A layer of mulch can reduce water loss and improve consistency
Fertilisation
Frost
Frost Tolerant
These plants can tolerate light to moderate frosts and may survive through cooler seasons.
Maintenance and Harvesting
Nasturtiums should be deadheaded and pruned to prevent sprawl. Water moderately and remove yellowing leaves. They benefit from regular picking to encourage more blooms and reduce self-seeding.
Pests and Diseases
Aphids
Aphids are tiny, soft-bodied insects that cluster on new growth and the undersides of leaves. They suck sap from plants, causing leaves to curl, yellow or become distorted. As they feed, they excrete sticky honeydew that encourages sooty mould, and colonies can build quickly in warm weather.
Start with organic controls: blast colonies off with a firm jet of water, encourage beneficial insects like ladybirds and lacewings, and spray neem oil or insecticidal soap to disrupt feeding. Keep plants well watered and avoid excess nitrogen that promotes soft growth. If pressure remains high, selective chemical sprays can be used sparingly, taking care to protect pollinators and beneficials.
Leaf spot
Leaf spot describes several fungal or bacterial diseases that create dark, often round lesions on foliage—sometimes with yellow halos. Severe infections cause premature leaf drop and reduced vigour, especially during warm, wet spells or when leaves stay damp.
Reduce spread by removing infected leaves, watering at the base, and spacing plants for airflow. Mulch to limit soil splash and rotate crops. Organic preventatives include copper and sulfur sprays applied early. If disease escalates, registered fungicides offer a chemical backup.
Downy mildew
Downy mildew causes pale yellow blotches on upper leaf surfaces with grey‑purple fuzz beneath, spreading fast in cool, moist weather. Heavily infected leaves collapse, slowing growth and yield.
Choose sunny, well‑ventilated positions, water early so foliage dries quickly, and remove infected leaves promptly. Organic options include copper and bio‑fungicides (phosphorous acid salts). For severe pressure, rotate chemical fungicide modes to prevent resistance.
Caterpillars & chewing larvae
Caterpillars and chewing larvae are moth and butterfly young that devour leaves or bore into stems and fruit, reducing growth and spoiling harvests.
Hand‑pick where practical and protect young crops with fine netting. Encourage parasitic wasps and birds. Apply Bacillus thuringiensis (Bt) for an organic, caterpillar‑specific control. Broad‑spectrum insecticides can work but may harm beneficials, so reserve for severe cases.
Leaf miners
Leaf miners can affect plant health and yields in home gardens. Typical symptoms include slowed growth, discolouration, and reduced productivity, often triggered by weather, nutrition, or cultural conditions.
Start with cultural fixes: rotate crops, improve soil with compost, water consistently, and choose resistant varieties. Organic sprays or amendments can reduce severity; chemical options are a last resort and should be used carefully and in accordance with labels.
Flea beetles
Flea beetles can affect plant health and yields in home gardens. Typical symptoms include slowed growth, discolouration, and reduced productivity, often triggered by weather, nutrition, or cultural conditions.
Start with cultural fixes: rotate crops, improve soil with compost, water consistently, and choose resistant varieties. Organic sprays or amendments can reduce severity; chemical options are a last resort and should be used carefully and in accordance with labels.
Growing Tips
• Nasturtium produces leaves not flowers in rich soils; avoid heavy feeding.
• Nasturtium trails and tangles; give space or support to reduce crowding.
• Nasturtium leaf quality declines in drought; water regularly for tender growth.
