When should I fertilise my lawn?
Quick answer
Feed when your lawn is actively growing. For warm-season grasses such as buffalo, kikuyu, couch and zoysia, that's from spring, once it's growing strongly, through to autumn. Cool-season lawns grow most in autumn and spring. Avoid feeding dormant lawns, heat-stressed lawns and lawns about to get heavy rain, and always use the rate on the label.
Why this happens
Fertiliser only helps a lawn that can use it, and a lawn uses nutrients when it’s actively growing. Warm-season grasses (buffalo, kikuyu, couch and zoysia) grow from spring to autumn, and in cooler zones they go dormant over winter. That gives you a simple rule: feed through the growing season, not in dormancy.
The first feed of the year is the one people most often get wrong. In temperate and cool areas, a warm-season lawn can look green-tinged in early spring long before it’s really growing. Wait until you’ve mowed a couple of times and it’s clearly growing before feeding. In subtropical and tropical areas the season starts earlier and finishes later.
Cool-season lawns (ryegrass, tall fescue, Kentucky bluegrass) do most of their growing in autumn and spring and struggle in summer heat, so they’re fed in those seasons instead.
How much and how often
Every product is different. The label tells you the rate per area and how often to re-apply, and slow-release products last longer between feeds than quick-release liquids. Measure your lawn and use the calculator so you apply what the label says.
When not to feed
Skip feeding when heavy rain is forecast, as it can wash fertiliser into drains and waterways; during heatwaves, when stressed grass can burn; and on a lawn that’s waterlogged or drought-stressed. Fix the water problem first.
What you may be seeing
- A lawn that has paled off or is growing slowly in the warm months
- Clover and other weeds moving into thin areas
It depends on your grass and climate
| If you have… | What changes |
|---|---|
| Tropical and subtropical areas | The growing season is long. Lawns may keep growing into early winter on the coast. |
| Temperate and cool areas | Warm-season lawns go dormant over winter. Wait until they're actively growing in spring before the first feed. |
| Zoysia | Zoysia needs less feeding than other warm-season grasses. |
| Kikuyu | Kikuyu responds strongly to feeding |
Rows that match the grass and climate zone you've set are highlighted. Set your climate zone
What you can do
Check the lawn is growingCheck first
If you've mowed once or twice and the lawn is clearly growing, it's ready to use a feed. If it's still dormant, wait.
Check the forecastCheck first
Avoid feeding before heavy rain or during a heatwave. Light rain or watering in afterwards is what you want.
Measure the lawn
Work out the area so you can apply the label rate, not a guess.
Apply evenly at the label rateProduct step
Use a calibrated spreader for granules or a hose-end sprayer for liquids.
Water in as the label saysProduct step
Granular fertilisers usually need watering in so they don't sit on the leaves.
What not to do
- Feeding a dormant lawn in winter in a cool zone and expecting a green-up.
- Doubling the rate to make up for a missed feed.
- Spreading by hand, which leaves stripes of dark and pale grass.
How much do I need?
A label rate of "20 mL per 100 m²" means: Rate 20, mL, per 100 m². Per hectare? Use 10,000 m².
How much you need
Enter your lawn area and a rate to see how much product and water you need.
Log it
Keep a record of what you applied, when, and at what rate. Your Lawn Journal works on this device without an account, and reminds you when the next step is due.
What's next
Related grass types, weeds, pests and diseases
Related questions
Related guides
Common follow-up questions
How often should I fertilise?
That depends on the product. Slow-release granules feed for longer than quick-release liquids. Follow the label for how often to re-apply.
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Sources
- How much water does my garden need?, Water Corporation (Western Australia)Overwatering can leach nutrients. Accessed 4 October 2026.
- Composition of nitrogen in urban residential stormwater runoff: concentrations, loads, and source characterization of nitrate and organic nitrogen, PLOS ONE (peer-reviewed journal), via PubMed CentralHeavy rain carries fertiliser nitrogen into stormwater. Accessed 4 October 2026.