Lavender – How to Grow, Maintain & Feed for Maximum Blooms

Lavender (Lavandula spp.) is a sun-loving, drought-tolerant plant adored for its fragrant purple flowers and silver-green foliage. Perfect for borders, hedges, feature pots, or pollinator-friendly gardens, lavender thrives in full sun and free-draining soil. When given the right care and nutrition, it rewards gardeners with extended flowering periods, strong stems, and vibrant, aromatic blooms that capture the essence of an Australian summer garden.

While lavender naturally performs well in low-fertility conditions, strategic feeding can significantly enhance its health and flowering capacity. Excess nitrogen encourages soft, leafy growth with fewer blooms, while a balanced fertiliser promotes sturdy plants and rich floral displays. Consistent but moderate feeding ensures your lavender remains compact, resilient, and continuously productive throughout the growing season.

For best results, apply Complete Grow’s NPK 20-20-20 Fertiliser at half strength during the growing and flowering season. This balanced formula supports healthy root development, vibrant foliage, and abundant blooms without the risk of over-fertilisation. Potted lavenders benefit the most from regular liquid feeding, as nutrients in containers are quickly depleted by frequent watering and active growth.

With the right combination of sunlight, well-draining soil, and a consistent 20-20-20 feeding routine, your lavender will deliver long-lasting colour, fragrance, and pollinator activity in your garden year after year.

How & When to Fertilise Lavender (In Pots or Garden Beds)

Lavender needs far less fertiliser than heavy feeders like tomatoes or citrus. In fact, too much nitrogen will reduce flowering and cause floppy growth. The key is light, infrequent feeding during active growth periods.

When to Feed Lavender in Australia

Early Spring (Sept–Oct): Apply a low-nitrogen fertiliser when new shoots appear.
Late Spring to Mid Summer: Feed once more during peak flowering to sustain blooms.
Autumn and Winter: Avoid feeding — lavender goes dormant and fertiliser won’t be absorbed effectively.

Feeding Lavender in Pots vs Ground

Potted lavender: Fertilise every 3–4 weeks using a diluted mix of Complete Grow 4-18-38.
In garden beds: Feed lightly once or twice per season. Too much fertiliser can disrupt natural growth rhythms.

Always water after fertilising and avoid feeding during extreme heat or wet weather. For best results, combine with a well-draining potting mix or sandy soil base.

Common Lavender Fertiliser Mistakes (and How to Avoid Them)

1. Using High-Nitrogen Fertilisers

Lavender doesn’t need leafy growth — it needs flowers. Fertilisers like lawn feed or high-NPK blends (e.g., 30-10-10) encourage excessive leafiness and reduce flowering. Stick to low-nitrogen, high-potassium options like Complete Grow 4-18-38.

2. Feeding Too Frequently

Lavender is adapted to nutrient-poor soils. Feeding every week can cause soft, leggy growth and reduce essential oil concentration. Feed just twice per growing season if planted in the ground, and once a month for potted lavender.

3. Not Adding Calcium or Magnesium

Lavender thrives in alkaline, mineral-rich soil. Deficiencies in magnesium or calcium can result in weak stems, yellowing leaves, and poor flower structure. That’s why Complete Grow’s Advanced Formula includes these key nutrients — especially useful for container-grown plants.

Want more blooms, better scent, and a stronger lavender plant? Use a fertiliser made for flowering species — like Complete Grow’s 4-18-38 or All Purpose 20-20-20 (at half strength) — and feed only when needed. Less is more with lavender!