Red Thread Lawn Disease! What it is AND How to Treat it!




Red Thread returns! What is Red Thread Disease?

Red thread is the most common lawn disease on UK shores. It can be identified as small pink needles of fungus which can form on grass leaves in the correct conditions. This, when well developed, can impact larger areas of turf and appear red, and then leave affected areas a brown / straw like colour after the attack has passed - with turf looking unsightly for days or even weeks. The good news is that Red Thread does not affect the roots of the grass plant, meaning a full recovery is made in time. With only the leaves damaged, these impacted areas 'grow out' with healthy green leaves following behind, when conditions allow.

For Red Thread disease to form there must be:


  • Mild to warm conditions

  • Wet conditions with prolonged rainfall and little drying time between

  • A level of humidity

  • Possible issues with airflow to the lawn

  • Possible issues with the use of a blunt mower blade when mowing

  • Possible issues with fertiliser inputs and soil quality

Are there preventative measures that we can take?


There are preventative fungicides which are applied at some golf courses and stadium environments in attempts to predict disease pressures a few days in advance. If the same conditions persist or return, so will the disease pressure at a later date. These fungicides have more of a place when protecting the turf from fatal diseases outbreaks rather than Red Thread - this is just the turf catching a summer cold. The lawns in our care are rarely stressed to a point where we have more sinister diseases to deal with.


Some lawn care services will treat for Red Thread. We view this as poor use of your money when it could go towards far more beneficial, preventative lawn care, along with in our opinion, not being a futuristic approach to sustainable lawn care.


Red Thread - What Can Be Done?

As touched on, there are a mixture of environmental factors which contribute to a Red Thread attack and a few things which are within our control such as:


  1. Airflow. Lawns surrounded by tall hedges, trees and buildings on all sides will be more likely to suffer - much like enclosed stadiums. If this can't be helped, then look to brush lawns during damp, humid periods so the grass isn't damp for long periods.

  2. By mid-summer you may have completed plenty of mowing; it might have been a winter where you skipped servicing your mower, or gave the blades maximum attention. Rotary blades cut the grass by bashing it rather than in the scissor-like action of a cylinder mower. This bashing, if not a clean cut, will allow disease to infect grass leaves far more readily.

  3. Heavy periods of rainfall on light soils may lead to the lawn becoming hungry and weak - a gap in the fertiliser programme. It is key that lawns receive slow-release fertiliser inputs with phased release patterns, and that lawns are neither over nor under fed.

Kingsbury Lawn Care | Lawn Treatment Service | Damaged Grass
Damaged grass leaves due to a blunt mower blade leaving the lawn more susceptible to Red Thread disease

How to Treat Red Thread


After ruling out preventative fungicides earlier in the blog, and taking on board that we cannot impact mother nature, we recommend:


  1. Good preventative lawn health along with an understanding of why the disease forms, and its cosmetic-only impact on our lawns.

  2. An understanding that we can 'grow out' the affected grass leaves through healthy growth. Application of a nitrogen based product, and / or products with levels of iron and magnesium will both help to grow these leaves out and green up the lawn.

  3. Checking if the mower is tearing at the leaves of the grass. Reassess the blade sharpness to see if airflow can be improved in any way. Reassess fertiliser applications - has it been too long since a fertiliser was last applied?

  4. When was the last time the lawn benefitted from mechanical work including overseeding with a modern professional seed mix? The latest seed mixes have greater red thread resistance to halt the spread and improve recovery time.


How can we help?


Our lawns have an excellent record with disease resistance, but of course this is still at the mercy of the weather. With our weather becoming increasingly unstable there is little doubt that we will be tested in years to come. We apply a very calculated nitrogen supply to our lawns with the intention of drip feeding our lawns all year round exactly what they need for their best chance. We work closely with homeowners to gain the very best from their green spaces. If we can be of further help, please speak to us on 01827 826123 or complete our 'Contact Us' form if lawn disease issues are something you wish to correct as a partnership.

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