GardenCalcs.uk
Lawn Feed Calculator — How Much Fertiliser for My Lawn
Calculate the right amount of lawn fertiliser for your grass area.
Measure or estimate your lawn area
Granular is easier to apply evenly; liquid gives faster results
Spring/summer = high-nitrogen greening feed; autumn = high-potassium feed to toughen roots for winter. Summer needs more frequent feeds.
Unit price for cost estimation
Leave at 0 to use seasonal defaults
Leave at 0 to use default size
How We Calculate This
Feed quantity = Lawn Area × Application Rate × Number of Applications.
Granular feed rates: Spring 35g/m², Summer 25g/m², Autumn 30g/m². Liquid concentrate: ~10ml/m² — a 1-litre bottle of UK lawn-feed concentrate (e.g. Westland SafeLawn Liquid, Miracle-Gro EverGreen) covers about 100m². The made-up watering-can solution covers far more area per litre; this calculator counts the concentrate you buy, not the diluted volume — always check your product label as dilution rates vary.
Number of applications varies by season: summer may need 2-3 feeds, while spring and autumn typically need one (granular) or two (liquid).
Frequently Asked Questions
Feed 2-4 times per year: spring (March-April), early summer (June), late summer (August), and autumn (September-October). Use the right seasonal feed.
Spring/summer feeds are high in nitrogen for growth and greening. Autumn feeds are high in potassium and phosphorus to strengthen roots for winter.
Yes. Over-feeding causes scorching (brown patches), excessive growth, thatch buildup, and environmental pollution. Always follow recommended rates.
Wait 2-3 days after mowing before applying feed. Water in granular feed if rain is not expected within 48 hours.
Over-feeding causes fertiliser burn: brown, scorched patches. If you spill concentrated feed, flood the area with water immediately. Always follow application rates carefully.
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.