When to fertilise your garden in Australia: the month-by-month guide

Ask ten gardeners when to fertilise and you will get ten answers. After 25 years feeding produce for Australian farms and markets, here is the calendar we actually use, adjusted for home gardens and for where you live.

The three golden rules

1. Feed plants that are actively growing. Fertiliser is fuel for growth. When a plant is pushing new leaves, roots, buds or fruit, it can use what you give it. When it is dormant in winter, most of that feed washes straight past the roots.

2. Match the feed to the phase. Leafy growth wants nitrogen. Flowers and fruit want phosphorus and potassium. That is why we make two feeds: Medigrow for the growth phase and Medibud for the bloom phase.

3. Little and often beats a lot at once. A dilute liquid feed every 1 to 2 weeks keeps nutrition steady without burning roots. With a concentrate that is 2.5 mL per litre of water, about 22 mL for a full 9 L watering can, sprayed on the leaves or watered in at the roots.

Month by month across Australia

September to November (spring)

The most important feeds of the year. Soil is warming, everything is waking up, and the growth you fuel now sets up the whole season. Start with a nitrogen-led feed for lawns, foliage, veggies and new plantings. As roses, citrus, tomatoes and flowering plants begin setting buds, switch those plants to a bloom feed. Feed weekly to fortnightly.

December to February (summer)

Keep feeding fortnightly, but time it well: early morning or evening, never onto dry, heat-stressed plants in the middle of a scorcher. Water first if the soil is bone dry. Fruiting crops like tomatoes, cucumbers and stone fruit are working hard now and reward a steady bloom feed. Lawns hold their colour with a light nitrogen-led feed monthly.

March to May (autumn)

The most underrated feeding window in Australia. Soil is still warm, so roots keep growing long after the air cools. An autumn feed strengthens lawns and perennials going into winter and is the secret behind gardens that bounce back fast in spring. Feed fortnightly through March and April, then taper off in May.

June to August (winter)

In cool and temperate zones, stop feeding dormant plants. Exceptions: winter veggies (brassicas, peas, leafy greens), sweet peas and spring bulbs pushing growth, and indoor plants, which just slow to a monthly feed. In frost-free warm zones, keep feeding anything actively growing, at a reduced fortnightly-to-monthly rhythm.

Adjust for your climate zone

Zone	Feeding window	Notes
Cool and temperate (Melbourne, Hobart, Canberra, Adelaide Hills)	September to April	Hard stop over winter for outdoor plants. Spring start can be late September.
Warm temperate (Sydney, Adelaide, Perth)	Late August to May	Light winter feeding fine for winter veggies and evergreens.
Subtropical (Brisbane, northern NSW, south-east QLD)	Almost year-round	Ease off only in the coldest weeks. Watch summer heat stress.
Tropical (Darwin, Cairns, Townsville)	Year-round	Feed lightly and more often in the wet season, as heavy rain leaches nutrients fast.

Which feed, when?

Think of the season in two phases. Phase 1, grow: nitrogen-led feeding for lawns, leaves, roots and structure. That is spring green-up, new plantings, seedlings and any leafy crop. Phase 2, bloom: phosphorus and potassium-led feeding from the moment buds appear until the last fruit is picked. Many gardens run both at once, with the lawn on phase 1 while the roses and tomatoes are on phase 2. That is exactly what the Whole-Garden Bundle is built for.

Common questions

Can I fertilise in the rain?

Light rain after feeding is actually helpful, as it waters the feed in. Avoid feeding right before heavy rain, which can wash liquid feed past the root zone before plants absorb it.

What happens if I feed in winter anyway?

On dormant plants, mostly nothing good: the feed leaches away unused, and on frost-tender plants a late nitrogen push can produce soft growth that frost damages. Save it for spring.

Is it possible to overfeed?

Yes, especially with granular fertilisers piled on in one hit. Dilute liquid feeding at label rates every 1 to 2 weeks is the low-risk way to feed, because each dose is small and immediately usable.

Every Medibud and Medigrow order is covered by the 30-Day Growers Guarantee: feed for 30 days, and if you cannot see a visible difference, we refund you.