Planting Guide: How to Grow Salvias from Seed
This guide will help you understand how to successfully grow Salvias from seed to full flower, offer tips to ensure healthy growth.
(Salvias are my favourite plant)
Flower Variety Identification
Common Name: Salvia
Scientific Name: Salvia
Family: Lamiaceae
When to plant Salvia in your climate
Not sure what your climate is? See our climate charts.
Cool: September, October, November, December
Temperate: August, September, October, November, December
Sub-Tropical: August, September, October, November, December
Tropical: February, March, April, May, June, July, August, September, October, November
Arid: Not suitable
Step by Step guide to growing Salvia
1. Choosing the Right Time to Plant
Salvia seeds can be started indoors or sown directly in the garden, depending on your local climate and temperature. Starting seeds indoors gives plants a head start, but in Australia’s warmer regions, seeds can often be sown outdoors.
When to plant:
- Indoor sowing: 8-10 weeks before the last frost (early spring).
- Outdoor sowing: Once temperatures consistently reach 15-20°C (late spring to early summer). In warmer parts of Australia, they can even be sown in early autumn.
2. Selecting the Ideal Location
Salvias thrive in full sun and well-drained soil, making them suitable for almost any garden.
Location needs:
- Full sun (at least 6 hours of sunlight per day).
- Well-drained soil, ideally with some organic matter.
- Avoid low-lying or wet areas that may retain excess moisture.
3. Preparing the Soil
Although salvia tolerates poor soil, you can enhance its growth with good soil preparation. Compost will improve soil quality and drainage.
Steps for soil preparation:
- Clear the area of weeds and debris.
- Loosen the soil to a depth of 30 cm.
- Mix in compost to improve structure and nutrient content.
4. Sowing Salvia Seeds
Salvia seeds are small and should be planted shallowly or simply pressed onto the soil surface.
Indoor sowing method:
- Fill seed trays with a light, well-draining seed-starting mix.
- Scatter the seeds on the soil surface and lightly press them in (avoid burying them).
- Keep the trays in a warm, well-lit area (around 20°C) and mist regularly to keep the soil moist.
- Seeds usually germinate within 2-4 weeks.
Direct sowing method:
- After the last frost, scatter seeds onto prepared garden beds and gently press them into the soil surface.
- Water carefully to keep the soil moist but not waterlogged until germination.
5. Watering and Care During Germination
While germinating, salvia seeds require consistent moisture. Avoid overwatering, which can lead to root rot and damping-off.
Watering tips:
- Keep the soil evenly moist but not soggy during germination.
- Once seedlings emerge, gradually reduce watering, allowing the soil to dry out slightly between waterings.
6. Transplanting Seedlings Outdoors
If you started your seeds indoors, transplant them outdoors once they are 5-10 cm tall and the risk of frost has passed.
Transplanting tips:
- Gradually harden off the seedlings by exposing them to outdoor conditions for a few hours each day over a week.
- Space plants 30-60 cm apart, depending on the variety, to allow for air circulation and growth.
- Water well after planting.
Three Growing Tips
1. Mulching for Moisture Retention and Weed Control:
Applying a layer of organic mulch around the base of the plants helps retain soil moisture, suppress weeds, and maintain consistent soil temperatures.
2. Prune for Bushier Growth:
Regularly pruning and deadheading salvia encourages bushier growth and more blooms. Cut back plants after flowering to encourage a second bloom cycle in warmer climates.
3. Choose a Heat-Tolerant Variety:
Many salvias are well-suited to Australia’s heat, but selecting a drought-tolerant, hardy variety will increase success.
Common Diseases and Pests
While salvias are generally pest- and disease-resistant, a few issues can occasionally arise:
Root Rot:
Often caused by poor drainage, root rot can lead to wilting and yellowing of leaves. Plant salvia in well-drained soil and avoid waterlogged areas to prevent this issue.
Aphids:
These small pests can cluster on new growth, causing distorted leaves and reducing plant vigour. Control aphids by spraying them off with water or using insecticidal soap if needed.
Powdery Mildew:
This fungal disease can occur in humid conditions, appearing as a white, powdery substance on leaves. Improve air circulation around plants, avoid overhead watering, and remove affected foliage to reduce mildew.
Spider Mites:
In hot, dry conditions, spider mites can cause stippling and yellowing of leaves. Increase humidity around the plants by misting or use insecticidal soap to control them.
Whiteflies:
These small, flying pests can affect salvia, especially in warmer coastal areas. Use sticky traps to catch whiteflies or spray leaves with soapy water to reduce infestations.
Read more on common plant diseases and how to cure them.
Aftercare For Salvias
Once established, salvias are relatively low-maintenance, but a few aftercare practices can keep them thriving:
Watering:
Salvias are drought-tolerant and only require occasional deep watering once established. In dry regions or during extended dry spells, water sparingly and allow the soil to dry between waterings.
Mulching:
Applying a layer of mulch around the base of the plants helps conserve soil moisture, suppress weeds, and keep the roots cool in the hotter parts of Australia.
Pruning:
Deadhead flowers throughout the season to encourage more blooms, and prune plants back after flowering to maintain shape and promote healthy growth.
Fertilising:
Salvias are not heavy feeders, but a light application of a balanced, slow-release fertiliser in early spring can help stimulate new growth. Avoid over-fertilization, as it can lead to excessive leaf growth and fewer flowers.
Winter Care:
In colder areas, salvias may die back in winter. Cut them back to ground level after the first frost, and in frost-prone regions, apply mulch around the base to protect the roots.
