Best Slow-Release Lawn Fertilisers of 2025

The Boston Seeds Lawn Fertiliser is designed for optimal growth from March to September, ensuring you apply the right nutrients when your lawn needs them most. With an NPK ratio of 20-6-8, it provides a balanced blend of nutrients for robust root development and vibrant foliage. The phased release of nutrients means you only need to apply it once for up to six months of sustained support, making lawn care simple and effective. Its granular formulation allows for steady nutrient supply, promoting consistent lawn health and vitality.

The Landscaper Pro Fertiliser is designed for effective lawn care, offering a slow release formula that lasts up to three months per application. This means you can apply it and enjoy a lush lawn without frequent reapplication. Its fast acting formula delivers results within just seven days, allowing you to see immediate improvements. Perfect for spring and summer, this fertiliser keeps your lawn vibrant during the growing season. Additionally, it comes in a convenient 5kg bag, ensuring you have enough to cover your lawn easily.

The Landscaper Pro Fertiliser is a slow-release lawn fertiliser that lasts up to three months with each application. Its fast-acting formula provides visible results in just seven days, ensuring your lawn looks its best quickly. This fertiliser is specially formulated for winter and autumn use, promoting steady growth while helping to reduce stress on your grass during the colder months. Supplied in a generous 15kg bag, it also includes a 100g pack of premium hard-wearing lawn seed for added convenience.

The Garden Lawncare Guy Fertiliser is a fast-acting solution designed to green up your lawn quickly. Packed with essential nutrients like nitrogen, potassium, and magnesium, it helps you achieve thicker and greener grass. You can apply it safely in gardens where children and pets play, as it doesn’t require toxic warning labels. With its dual-action formula, it feeds your grass for up to 90 days, ensuring a long-lasting lush appearance without the worry of brown stains on your hard surfaces.

The Elixir Gardens Lawn Fertiliser is designed specifically for the British climate, making it ideal for your garden. It contains 5.2% sulphur, which promotes overall grass health, and 2.6% magnesium, helping to harden turf during winter. This fertiliser reduces plant stress and supports healthy root development through the colder months. It also protects your plants from harsh winter conditions like strong winds and snow, ensuring your lawn stays vibrant and resilient.

The Grass People Fertiliser offers premium protection for your lawn during the autumn and winter months. It helps prevent winter diseases like Red Thread and Fusarium Patch, ensuring your lawn stays healthy. This slow-release feed promotes growth from August to November, giving you a lush sward come spring. With high levels of potassium, it strengthens your lawn's root system, making it less susceptible to disease. The instant application makes it easy for you to achieve a beautifully protected lawn without hassle.

The URPril™ Nitrogen Fertiliser is a powerful 46% nitrogen formula designed for various plants, including grass, trees, and shrubs. It can be used as a top dressing or in a water-soluble form, giving you the flexibility to choose the best method for your garden. This fertiliser provides a significant green boost, ensuring your plants thrive with lush foliage. Whether you are caring for vegetables, pot plants, or lawns, this product helps you achieve vibrant growth effortlessly.

The Ivisons Summer Fertiliser is designed to keep your lawn healthy during the warm months. With its slow-release formula, it nourishes your grass for up to 8-10 weeks, ensuring it remains green and robust even in summer heat. The homogeneous granules provide an even spread of nutrients, avoiding the patchy growth often caused by cheaper alternatives. This high nitrogen mix is vital for promoting strong growth and vibrant colour, making your lawn the envy of the neighbourhood.

URPril™ Nitrogen Fertiliser is a versatile product that offers a slow release of nutrients, ensuring your plants receive a steady supply of nitrogen. This water-soluble formula means you can easily mix it with water for quick application or use it as a top dressing for your lawn. With 46% nitrogen content, it effectively boosts the growth of grass, shrubs, and trees, promoting a lush and healthy appearance. Its small spherical prills are easy to handle, making fertilisation a hassle-free task for you.

Nutrigrow Lawn Fertiliser is designed to provide a lasting boost to your lawn. With a longevity of six weeks, you can enjoy the benefits without frequent reapplication. You will notice a positive response from your turf within just seven days, making it ideal for quick results. The granular form allows for easy application and even distribution, ensuring that every part of your lawn receives the nutrients it needs. This product releases nutrients slowly, preventing rapid top-growth and promoting healthier turf overall.