How To Avoid Lawn Disease And Cure Your Lawn Problems 

    Lawn disease is the last thing you want this summer. It’s something that affects a number of gardens in the UK and can be confusing, as it’s often difficult to identify the cause.It’s good to keep in mind that lawn diseases are most commonly fungus and can be treated easily. An early diagnosis is important to ensure that the disease does not spread and damage the rest of the lawn. There are 3 common types of lawn disease in the UK; Red Thread, Fusarium and Leaf Spot. (Image of Leaf Spot shown below © RHS)


    Red Thread

    The most common lawn disease in the UK is Red Thread – which typically affects lawns which have poor light and soil. Symptoms often occur after periods of heavy rain, as it washes away nitrogen from the soil.

    The late summer is a common time in which Red Thread can be seen. You should be able to notice this when inspecting your lawn. Simply look for red needle like threads growing on your grass leaves.

    Interestingly, the thread-like structures (stromata) can actually survive on leaf debris and in soil for up to two years. Spread of the disease can occur by airborne or waterborne spores, or on contaminated tools or shoes. Worry not however, Red Thread is more of a leaf disease so is unlikely to kill the root system meaning turf can recover adequately given time.

    How to treat Red Thread

    An application of nitrogen to the affected area of Red Thread is often an effective way to control it. Nitrogen is best given as sulphate of ammonia at 15g per sq m (½oz per sq yd) – always follow the directions on the fertiliser box. Do not apply after August to avoid the production of soft growth which is prone to snow mould. 


    Also known as Microdochium Patch or Pink Snow Mould, Fusarium is a disease which is often found in fine turf. It is caused by a fungus called Microdochium nivale and can appear on lawns, particularly after periods of prolonged snow which has given your lawn a sustained covering. Symptoms of this disease can first appear as small circular soaked patches and then lead to the discolouring of grass. Grass colour will change to orange / brown, then to a darker red-brown, ultimately then progressing to a tan / straw colour.

    How to treat Fusarium

    The best way to treat and prevent this comes through good soil fertility. Invest in a fertiliser with low levels of nitrogen for this disease, these are usually classed as autumn/winter fertilisers. In addition to this make sure you’re mowing regularly and using a lawnmower with a sharp blade. 

    Leaf Spot

    Occurring mostly in the summer months of high temperatures and high humidity, Leaf Spot is a disease which is easily recognisable. Something you’ve probably seen before, the infected area turns a pale brown and looks burnt with a ring of yellow. Leaf Spot is actually a common name given to a large range of lawn diseases, caused by the same family of fungi.

    How to treat Leaf Spot

    Early action is important and how the turf is watered, fed and mowed makes a difference for this. Try to make sure that grass does not stay continuously wet or become excessively dry. Water no more than once per week and do this in the morning - this allows turf to dry throughout the day. Aerating your lawn frequently is a good way to combat Leaf Spot and, as always, a good fertiliser is recommended. 

    5 tips to avoid lawn disease

    1. Don’t Over-water – most lawn diseases thrive when grass is constantly wet for long periods of time

    2. Don’t mow too low – did you know you should aim to cut only 1/3 of the grass blade when you mow? Mowing too low creates grass conditions that diseases love, and excessively stresses the grass.

    3. Make sure your blade is sharp - this prevents fraying the tips of the grass blade. This fraying leads to the grass dehydrating which causes yellowing of the grass tips – You can purchase Flymo Genuine replacement blades from our shop.

    4. Fertilise well – Ask at your local garden centre for the correct fertiliser for your lawn problems

    5. Frequent aeration – Aeration is the practice of punching small holes into your turf to allow air, water and nutrients to the grass roots. This helps produce a stronger, more vigorous lawn to fight off disease.

    The Royal Horticultural Society grants Flymo a licence to use the supplied image(s) free of charge for one time use only on Flymo blog post on lawn diseases. The images cannot be distributed and must be deleted after use. Images must be clearly credited as © RHS. Images cannot be altered without prior consent. Any infringement of these terms and conditions will result in the termination of the right to use the image(s). The RHS reserves the right to revoke this license at any time.