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Grass Seed Calculator

Calculate how much grass seed you need for new seeding or overseeding your lawn

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🇩🇰 All calculations are based on Danish rules, rates, and currency (DKK). This calculator is translated for convenience but applies exclusively to Denmark.

Calculate grass seed for your lawn

Our grass seed calculator helps you determine the exact amount of grass seed needed for your lawn. Whether you're establishing a brand new lawn or overseeding thin patches, you'll get the right number of kilograms and bags.

New seeding vs. overseeding

For new seeding, approximately 30 grams of grass seed per m² is recommended. This ensures a dense and uniform lawn from the start. For overseeding, where you only need to repair thin areas, 15 grams per m² is sufficient, as existing grass plants already cover part of the area.

When to sow grass seed

The best time to sow grass seed is spring (April-May) or late summer (August-September). The temperature should be above 10°C and the soil should be moist but not wet. Avoid sowing during dry or very hot periods, as seeds need consistent moisture to germinate.

Choosing the right grass type

The most popular grass types for lawns include a mix of ryegrass, Kentucky bluegrass, and red fescue. Choose a blend that suits your needs – shade-tolerant grass for shaded areas or hard-wearing grass for the family play area. Remember to water regularly for the first 2-3 weeks after sowing.

Frequently Asked Questions

How much grass seed do you use per m²?

For new seeding, 30 grams per m² is recommended to achieve a dense and uniform lawn. For overseeding, 15 grams per m² is sufficient. The amount may vary slightly depending on the grass type – finer grass varieties typically require slightly more seed.

When is the best time to sow grass?

The best time to sow grass is spring (April-May) or late summer (August-September). The temperature should be at least 10°C and the soil should be kept moist for the first weeks. Late summer is often ideal as the soil is still warm and there is typically more rainfall.

How many bags of grass seed should I buy?

The calculator uses standard 1 kg bags. Multiply your area by 30 g/m² (new seeding) or 15 g/m² (overseeding) to find the total amount in grams, then divide by 1000 for kilograms. Always round up so you don't run short. Consider buying a little extra for patching.

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