What fertiliser should you use on a UK lawn?
The right lawn fertiliser depends on the time of year. In spring and summer, use a fertiliser high in nitrogen (N) to promote leaf growth and that deep green colour. A typical spring feed has an NPK ratio around 12-4-6. In autumn, switch to a feed high in potassium (K) and phosphorus (P) to strengthen roots and harden the grass for winter, such as an NPK of 3-12-12. The numbers represent the percentage of nitrogen, phosphorus, and potassium by weight. Nitrogen drives top growth, phosphorus supports root development, and potassium improves disease resistance and drought tolerance. Never apply a spring/summer feed in autumn, as the nitrogen pushes soft growth that is vulnerable to frost and fungal disease.
How often should you fertilise a UK lawn?
Most UK lawns benefit from three feeds per year: spring (March or April), early summer (May or June), and autumn (September or October). This is the schedule recommended by the Royal Horticultural Society. Lawns under heavy use, such as family gardens with children and pets, may benefit from a fourth feed in midsummer. Newly laid turf should be fed six weeks after laying. Newly seeded lawns should not be fed until the grass has been mowed at least three times. Over-fertilising is worse than under-fertilising: excess nitrogen causes rapid, weak growth that is prone to disease and needs more frequent mowing. Always follow the application rate on the product label.
Organic vs synthetic lawn fertiliser: which is better?
Both types work. Synthetic fertilisers deliver nutrients quickly and are available in precise formulations, making them effective for fast results. They are the most popular choice for UK lawns. Organic fertilisers (such as bone meal, blood meal, seaweed extract, and composted manure) release nutrients more slowly as soil microbes break them down. This gives a steadier, longer-lasting feed and improves soil structure over time. The trade-off is that organic feeds are slower to show results and harder to apply evenly. Many professionals, including ELawnCare, use a combination: synthetic feeds for spring green-up and autumn hardening, and organic top-dressings annually to build long-term soil health.