How to calculate your lawn seed sowing rate – How much lawn seed do I need to buy?
One of the first steps to creating a professional quality lawn is accurately calculating how much seed to buy. Whether you are starting from scratch or refreshing an existing yard, getting the sowing rate right is an important first step.
What is a Sowing Rate?
A ‘Sowing Rate’ is the specific amount of seed required to effectively cover your lawn area (usually measured per square metre).
Why do rates differ?
Rates differ due to the growth habit of the variety:
- Couch & Kikuyu: Couch & Kikuyu lawns grow sideways via runners and fill in over time. This means you need a lower volume of seed to achieve a full lawn over time they have a lower rate of roughly 1kg per 100sqm.
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Fescues & Ryegrass: These finer varieties require a higher rate of around 3kg to 5kg per 100sqm to ensure dense coverage.
Measure Your Lawn Area
Begin by finding out the size of your lawn. For simple rectangular lawns, just pace it out (1 large step is roughly 1 metre). For more complex shapes, use the guide below to break your lawn into manageable sections.
Pro Tip: If your lawn is an irregular shape, draw it on paper first. Divide it into squares, triangles, or circles, calculate each, and add them together for your total area.
Got some lawn cover?
- New Lawns: This requires the full sowing rate to ensure dense coverage.
- Oversowing/Repair: If you have half already covered you can halve the sowing rate. Estimate the amount of cover and reduce the rate down accordingly.
Don't Forget the Starter Fertiliser
To give your new seeds the best start, use a Starter Fertiliser. Unlike standard fertilisers, a starter blend has a specific NPK balance (Nitrogen, Phosphorus, and Potassium) designed to stimulate deep root development and fast germination.
Top Pick: Landscape Range KickStart Fertiliser for lawn seed sowing.
- Application Rate: 3kg per 100sqm.
Once you have your area (sqm) and your product rate, the math is easy:
(Lawn Area ÷ 100) x Sowing Rate = Total Seed Required
Example: If you have a 50sqm lawn and your chosen seed rate is 4kg per 100sqm: (50 ÷ 100) x 4 = 2kg of seed needed.
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