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Fertiliser Calculator

Calculate how much fertiliser you need for lawn, flower bed or vegetable garden

m²
🇩🇰 All calculations are based on Danish rules, rates, and currency (DKK). This calculator is translated for convenience but applies exclusively to Denmark.

Calculate fertiliser for your garden

Our fertiliser calculator helps you determine how much fertiliser you need for your lawn, flower bed or vegetable garden. Correct fertilisation is essential for healthy plants and great results.

Fertiliser amounts by garden type

Different garden types have different nutrient needs. A lawn typically requires 30 grams of fertiliser per m² per application, while flower beds need about 50 grams and vegetable gardens 60 grams per m². This is because vegetables and flowers have higher nutrient requirements than grass.

How often should you fertilise?

Most gardens benefit from three fertiliser applications per year: spring (April), summer (June-July) and autumn (September). This provides plants with nutrition throughout the growing season. Consider using slow-release fertiliser that releases nutrients gradually over 2-3 months.

Fertilising tips

Always fertilise on moist soil and water afterwards so nutrients dissolve and penetrate to the roots. Avoid fertilising in strong sun or drought. For lawns, a specialist fertiliser with high nitrogen content is recommended, while flowers and vegetables benefit from a more balanced NPK fertiliser.

Frequently Asked Questions

How much fertiliser should you use per m²?

It depends on the garden type. Lawns need about 30 grams per m², flower beds about 50 grams, and vegetable gardens about 60 grams per m² per application. These amounts apply to standard fertiliser – always follow the manufacturer's instructions for your specific product.

When should you fertilise the lawn?

The lawn should be fertilised three times a year: first in spring (April) when the grass starts growing, again in midsummer (June-July), and a final time in autumn (September). Use spring fertiliser with high nitrogen content and autumn fertiliser with extra potassium to strengthen the lawn against winter cold.

Can you over-fertilise?

Yes, too much fertiliser can burn the grass and damage plants. Over-fertilisation typically shows as yellow or brown patches. Always follow recommended amounts and water thoroughly after fertilising. If you've over-fertilised, heavy watering can help dilute the nutrients in the soil.

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