"When should I fertilise my lawn?" is one of the most searched lawn questions in Australia, and the answer depends entirely on where you live. In Ipswich and the Springfield corridor our lawns are warm-season grasses (buffalo, couch, kikuyu, zoysia) that grow hard from spring to autumn and slow right down in winter. Fertilise when they are growing and you get a thick green lawn. Fertilise when they are dormant and you mostly feed the weeds.
The Queensland lawn fertilising calendar
Early spring (September): the main feed
Once night temperatures stay above about 12°C and the lawn is visibly growing again, give it a full-rate application of a balanced slow-release lawn fertiliser. This is the most important feed of the year. It kick-starts growth, thickens the lawn before summer and helps it crowd out weeds.
Early summer (late November to December): the top-up
A lighter second application before the heat sets in keeps colour up through the storm season. If you are using a slow-release product this can be a half rate. Water it in well, ideally before rain.
Autumn (March to April): the recovery feed
After a hot summer, a balanced feed in early autumn repairs wear, thickens the lawn before winter and sets it up to green up faster in spring. Look for a product with a bit more potassium, which helps the grass cope with cold and stress.
Winter (June to August): leave it
Warm-season grasses are dormant or barely growing in an Ipswich winter. Fertiliser applied now sits in the soil, leaches with winter rain or feeds winter grass and broadleaf weeds. The exception is a dedicated iron or "winter green" product, which colours the leaf without pushing growth.
What to use on each type of grass
- Buffalo (Sir Walter, Sapphire, Palmetto): a slow-release lawn fertiliser with a moderate nitrogen rate. Buffalo does not like being pushed with high-nitrogen fast-release products; it goes soft and thatchy.
- Couch: handles higher nitrogen well and responds fast. Feed a little more often, but keep mowing regularly or it will thatch up.
- Kikuyu: the hungriest and fastest grower. Moderate nitrogen is enough; more just means more mowing.
- Zoysia: light feeder. One spring and one autumn application is usually plenty.
How to apply it so it works
- Mow a day or two before, so the fertiliser reaches the soil rather than sitting on long leaf.
- Apply at the label rate with a spreader for an even result. Hand-throwing gives you stripes.
- Water it in straight away (or apply just before steady rain). Fertiliser left dry on the leaf can burn the lawn, especially in summer.
- Do not fertilise a drought-stressed, grub-damaged or freshly laid lawn. Fix the problem first, feed second.
Granular vs liquid
Granular slow-release is the backbone: three or four applications a year does most of the work. Liquid or hose-on products are useful for a quick green-up before an event or an inspection, but they only last a few weeks. Organic pelletised products are gentle and improve the soil, but you need more of them and they can attract dogs.
Frequently asked questions
What is the best month to fertilise a lawn in Queensland?
September, once the lawn is actively growing again. A second lighter feed in late November and a recovery feed in March or April round out the year.
Should I fertilise my lawn in winter in Queensland?
Generally no. Warm-season grasses are dormant and will not use it. If you want winter colour, use an iron-based product rather than a growth fertiliser.
Can I fertilise before rain?
Yes, light steady rain is ideal because it waters the product in. Avoid fertilising before a heavy storm, which washes it off the lawn and into stormwater.
How long after fertilising can I mow?
Wait until the fertiliser has been watered in and the lawn has dried, usually two to three days. Mowing straight away can pick up the granules.
