The use of fertiliser is one of the key steps in maintaining a healthy lawn, but understanding how to apply it correctly can be confusing. Too much fertiliser and your grass may burn or grow excessively and too little can cause weak, patchy or yellow grass. So, how often should you fertilise your lawn? The answer depends on the type of grass, the condition of your soil, the time of year, and the kind of fertiliser you use.
Why do I Need to Fertilise my Lawn?
Lawn fertiliser contains three essential nutrients – nitrogen, phosphorus, and potassium which contribute to strong grass growth, a rich, deep colour, and healthy root development. These nutrients occur naturally in the soil but can become depleted over time through mowing, rain and general wear and tear, and need to be replenished.
Seasonal Fertilising Guide
Adopting a seasonal approach to lawn fertilisation works well here in the UK, as our changeable climate means the nutrient needs of our lawns will differ throughout the year.
Spring Fertilising (March to May)
As temperatures start to rise, the ground warms up, and growth restarts after winter, spring fertilising is the most important feed of the year. Apply a high-nitrogen fertiliser such as KissMyGrass Spring & Summer Lawn and Sportsfield Fertiliser 11.5.5 to encourage lush, green growth. With a slow-release formula, this is ideal, as it feeds the lawn gradually over 6–8 weeks.
Summer Fertilising (June to August)
When a lawn is actively growing and regularly mowed, a second feed in summer helps to maintain its colour and strength. Choose a balanced fertiliser that will support ongoing growth without encouraging too much top growth, beneficial during dry spells. KissMyGrass Premium Spring & Summer Lawn and Sportsfield Fertiliser 12.5.5+ has a balanced blend of nutrients for healthy growth as well as iron, magnesium and seaweed.
Autumn Fertilising (September to October)
An autumn feed is beneficial to prepare your lawn for winter. Switching to a fertiliser with lower nitrogen and higher potassium will toughen the grass and strengthen roots. KissMyGrass Autumn & Winter Lawn Fertiliser 6.5.10 + Fe + Mg helps to protect against turf diseases and gives a deep green colour.
Winter Fertilising (November to February)
Many gardeners avoid fertilising in winter when grass growth slows right down, believing that applying fertiliser can do more harm than good. However, using a specialised winter feed such as KissMyGrass Winter Defender Liquid Lawn Fertiliser, will protect lawns against diseases without promoting growth.
Is it Possible to Over Fertilise my Lawn?
Over-fertilising can lead to rapid, weak growth, thatch build-up, and nutrient runoff. This isn't just bad for your lawn but it’s also bad for the environment.
Generally, fertilising three times a year — in spring, summer, and autumn — is enough for most UK lawns. If you’re using a slow-release fertiliser, such as KissMyGrass Slow Release Lawn Fertiliser 20.6.8 (3 month), you may only need two applications - one in spring and again in autumn.
Liquid lawn fertilisers (such as KissMyGrass Winter Defender Liquid Lawn Fertiliser) should be applied every 3-4 weeks, but always exercise caution to avoid overfeeding.
How to Get the Best Results When Fertilising
• Test your soil every couple of years to check nutrient levels and pH. as the needs of your lawn will vary over time, requiring a different balance of nutrients.
• Always mow before fertilising, but don’t cut the grass too short.
• Water the lawn after applying fertiliser, unless rain is forecast.
• Use a lawn spreader for even distribution and to avoid patchy results.
• Always read the label for specific instructions based on the product you’re using.
Lawn Fertiliser from Boston Seeds
Feeding your lawn isn’t complicated with Boston Seeds! With our wide choice of lawn fertilisers, including granular lawn fertiliser and liquid lawn fertiliser, we offer everything you need to maintain a seasonal routine to keep your grass looking its best. Be mindful of weather conditions, your lawn's growth pattern, and any visible signs of stress — they’re all good indicators of what your lawn needs and when. A little care throughout the year goes a long way toward a classic green lawn.
For specific help on which fertiliser to use or any other fertiliser queries, our Lawn Fertiliser Advice and Tips contain lots of informative articles. And, of course, our expert team is available to answer any questions. Simply contact us by email or call us on 01205 280 069.
