Download Technical Leaflet - Worm Casts
What are they and where have they come from?
Over the late autumn through to spring period, you will notice small mounds of soil on the surface of the lawn. The casts are the work of earthworms that live in the root zone of the soil. There are five types of casting worms found in British soils and numerous non-casting worms too. The worms eat the soil, digesting and extracting the goodness from it as it passes through their bodies. The by product of their diet is the casts which are pushed up as they work through the soil, cleaning their burrows, much like a mole hill.
Why are worm casts a problem for lawn owners?
It is not the activity of the worms naturally aerating the soil beneath the grass surface, but the detrimental effect of their casts that cause the problems. The soil making up the casts is very slimy as it consists of soil and the natural secretions from the worm’s digestive system. Left on the surface of the lawn, the casts will be smeared across the grass through the actions of mowing and walking on the lawn. The end result is that worms are capable of pushing up an incredible volume of soil by way of their casts so it does not take long for the surface of the lawn to become really muddy and slippery.
When do the casts appear?
As the soil air to water ratio changes in the more traditional autumn months, you will notice an increase in worm cast activity. The wetter the autumn or winter, the greater the worm activity will be. The root zone of the lawn will become spongy as the worms undermine the upper surface and mowing will become difficult, especially with a cylinder mower. The use of the lawn will diminish as a result of the difficult surface conditions.
What can be done to control the worm activity?
Worms prefer rich organic soils that are full of bacteria and soil flora and fauna. Increased populations can be found in heavier clay soils and wetter soils.
Prevention is always better than cure - leaving autumn leaves on the surface of the lawn for long periods will encourage worms to literally pull the leaves into their burrows. Leaving lawn-mowing clippings on the lawn will increase worm activity as the dead and decaying matter is increasing the organic matter content of the soil – a rich food source for worms.
Culturally, you can switch the casts off the lawn on a dry windy day with a besom broom or bamboo cane. This is not 100% ideal if the there are numerous casts though!
The best solution is to apply a worm cast control product in late September/October. The control product does not kill the worms but creates a barrier in the soil that the worms are not keen to pass through, as the control product is an irritant to their system. The worms will stay deeper in the soil and not cast.
Domestic Lawn Use - CastClear Lawn Worm Cast Suppressant
Professional Turf Use - Contract Pesticide Application Service - Weed Free
The pesticide control product will last around two to three month’s dependant upon the level of rainfall over the autumn/winter months. Do not be tempted to spray too early in September. CastClear will need re applciation every 10 - 20 days until the worm cast activity has been eradicated.
The pesticide control product is only available to professional pesticide users that hold a Certificate of Competence to purchase and apply such products.
The results following worm cast control application are quite remarkable. Adopting a worm cast control programme maybe once of twice a year in really high activity areas will not only go a long way in securing the grass cover over the autumn and winter months but lengthen the actual mower season.
Increased maintenance costs
As the worm casts are predominately dirt, it will not take long for the cylinder mower blade to loose its sharp edge as it literally grinds away the leading and cutting edge, thus increasing maintenance costs.
The worm casts are a bacteria rich soil, which means that weed seeds are easily able to germinate in them, thus increasing the number of weeds the following spring. The casts when trodden on can be squashed and then smear on the surface of the lawn thus smothering any grass that was there beforehand – so in time you can literally loose your lawn to a sea of worm casts that turn to mud!
An amazing fact about earth worms –
Worms are the richest source of protein known to man, which explains why I spent such a long time trying to eat them when I was young….
You mention leaving lawn-mowing clippings on the lawn will increase worm activity as the dead and decaying matter is increasing the organic matter content of the soil – a rich food source for worms. However, a lot of areas say to leave the lawnmower clippings as it encourages growth, ph and so on. So, am somewhat puzzled but I do agree in that when I have left grass clippings, worm casts are abundant all over my lawn. So I stop leaving the lawn clippings?
Reply: Earthworms love organic matter. If you mow on a very regular basis, the mown vegetation will burn off in the sun in small amounts rather than a greater mass of mown debris.
Posted by: LH | October 10, 2021 at 19:26
My back yard has worm and at night animal I do not know what kind comes and made hole to remove worm. Please let me know what product show I use. Thanks
Reply: Use www.CastClear.co.uk
Posted by: Massy | May 01, 2019 at 17:12
Hi, is it safe to overseed a bowling green after applying a worm surpressant? (Will the seed or its ability to germinate be effected)? If it is not safe then how long is a safe period of time before overseeding? Thanks.
Reply - it is was Carbendazim, then yes.
Posted by: Ian muskett | September 29, 2016 at 14:30
The best way to rid worm casts is to suck them up with a wet and dry vacuum.
Reply - Use www.CastClear.co.uk to control them.
Posted by: k.moralee | September 04, 2015 at 12:04
Hi we are about to lay new lawn but have suffered previously with really bad worm cast. Do we apply the worm cast control product before or after we lay the lawn? Also as it does not totally eradicate the problem will we need to re-apply the worm cast control product regular every 2 - 3 months? If so this is going to be an expensive way to treat it. Is there no permanent solution?
REPLY - visit www.CastClear.co.uk Worm will be active September through to April dependant upon what type of spring we get. Currently is was a wet one = lots of lawn worm casts.
Posted by: Vikky | March 19, 2015 at 21:30
I have no interest in killing my worms - they're part of the natural fauna of my lawn - but having had a new lawn laid in the autumn - then that lawn having spent most of the winter and spring at water table level - I assume the worms have been gasping for air and trying to escape drowning - so my small lawn now consists of rather water abused grass and a mass population of worm casts - my aim is to try to brush them flat and we have had a week of dry weather - but they do seem to be a bit resistant to flattening - I am on London clay - how can i gently flatten these worm casts - I intend to sprinkle lawn dressing in the under grassed patches and reseed - I have no intention of getting rid of any worms - I value the earths natural organisms
Reply - use www.CastClear.co.uk It will not harm the worms as we agree they are so important!
Posted by: Lucy Blake | March 16, 2014 at 14:57
We had artificial grass laid down last summer. Over the autumn we noticed worm mounds appearing all over the grass. Is there something we can use to deter them. Obviously we don't need a treatment that will effect the grass seeing as it isn't real. Our beautiful artificial grass now looks horrid due to mud smears when we brush them away.
Thanks
Reply - www.castclear.co.uk will solve the problem. Artificial lawns are not maintenance free sadly and will suffer from pests and weeds and moss and an uneven surface over time. The product will be quite safe to apply to the plastic grass.
Posted by: Champs | March 10, 2014 at 10:20
Does worm cast still happen middle-end of October I recently changed my blade on my mower and when I do my garden noticed mud patches which I assumed was a dodgy blade after taking my mower back I was assured it wasn't my new blade causing the problem the problem has happened on my mothers and grandmothers garden with the same mower it is a self propelled rear rolling mower.
Reply: It's worm castings. Control with www.castclear.co.uk
Posted by: aidan parr | October 25, 2013 at 16:40
Hello!
Im happy to hear there's a treatment against worm casts. I really want it. But do you sell it to Bulgaria or ship it?
Thanks!
Reply - we can ship it to Europe.
Posted by: Ilian | March 07, 2013 at 12:48
One of natures natural fertilizers as well as insect and disease repellents is called a worm casting. These small nodules are created by red worms as they participate in the composting process, something that they naturally do and have done for millions of years.
Reply - it's not the worms that are a problem for lawn owners, just their casts.
Posted by: steam cleaners | December 19, 2012 at 17:00
Many experts prefer electric power machine systems when it comes to treating challenging washing projects. Stress units are highly effective washing machines that use tremendous pressure to boost away dust gathered on almost any hard surface. Stress cleaning solutions are particularly effective in washing commercial flooring surfaces and equipment where the washing needs are difficult and more extreme.
Posted by: steam cleaners | December 19, 2012 at 10:36
I am also very fed up with the termites in my lawns and I think your lawn advice blog will really helps me to get some good updates about it.
Posted by: Dermatologist in Brisbane | November 12, 2012 at 11:12
Every year my worms start leaving casts in early September, the grass does not seem to grow under these, causing my lawn to be quite sparse in spring of the next years. However this year i thought it would be better as we have had no rain in British Columbia for about 2 months now. This year i tried pressure washing the lawn. (only spot pressure washing i guess it would be called). This seems to get rid of the piles and hopefully i will not have to re seed next year. Will this cause further damage somehow?
Reply - it sounds a bit drastic to us but if it works. Making the surface really moist may cause some rotting to occur so control of the problem may be the key.
Posted by: Peter Dunn | October 01, 2012 at 22:58
Extraordinarily significance info! just right what I was seem to be!
Reply - happy to help. The advice is free always
Posted by: Katy Hepburn | August 08, 2012 at 12:25
Cheers! A very superior read. Added your lawn blog to bookmarks so I will visit back for new content and to read other peoples comments Thanks again.
Reply - thank you!
Posted by: Screen Golf | July 30, 2012 at 13:19
Is there anything I can do at this time of the year? My lawn is terrible and want to get it sorted for the spring?
Reply - timing is just great if the spring is kind weather wise. Read the post How to Renovate a Lawn and you will be well armed! Also take a look at www.thelawnshop.co.uk for products.
Posted by: Mick Beanse | March 07, 2012 at 07:30
Thanks for sharing such an educational post! Keep posting. =)
Posted by: Synthetic Turf | February 04, 2012 at 21:24
Worms produce worm casts (small piles of digested earth), which are unsightly, slippery, blunten lawn mowers, affect play on sports turf (e.g. bowls, croquet and golf) and make balls, etc. unpleasant to handle.
The casts also can act as seedbeds for weeds. The action of worms can also facilitate weed growth by pulling down seed material from the surface.
Posted by: | January 21, 2012 at 08:12
Oh my god..five types of casting worms found in British soils. In my opinion, we must be very careful while gardening.
Reply - thanks for reading our Blog
Posted by: | October 31, 2011 at 03:51
Thanks for this article. We have only had our lawn for a year and casts have now began to appear. I was slowly watching my lovely lawn turn to mud, so your article has given me hope of saving it. Once again, thank you for the information.
Reply - our advice is free and timely so please tell your family and friends and colleagues!!
Posted by: Andrew Tusabe | October 30, 2011 at 20:40
One of my clients has just laid a new lawn about a month ago and has worm casts is this the best way of getting rid of them.
Reply - You do not get rid of them, simply deter them from casting. See www.thelawnshop.co.uk to buy CastClear to get rid of worm casts on your lawn
Posted by: Lisa | October 17, 2011 at 18:05
Worm casts can be removed mechanically by brushing, switching or using a drag mat. Brushing is only feasible for small areas. Switching involves using a long switch, like a fishing rod, the end of which is swept quickly over the surface of the grass.
Reply - we agree but also the use of a Worm Cast Deterrent will help ay cultural practices like brushing, switching and harrowing or drag matting the dry casts over the lawn as if they were top dressing. Only dry and crusty worm casts may be brushed etc and wet ones only smear the lawn grasses.
Posted by: Artificial Grass | April 26, 2011 at 06:12
Hi
Is this safe to use in a household that has young children and cats?
Thanks
Reply - yes on all counts. Just keep them off for 24 hours following application. It will leave a little smell for a few days in the air but it soon wears off.
Posted by: mandi townsend | September 28, 2010 at 15:09
Is the worm cast control solution harmful to children I have 2 young children that play and roll around on the lawn.
Reply - yes on all counts. Just keep them off for 24 hours following application. It will leave a little smell for a few days in the air but it soon wears off.
Posted by: me.yahoo.com/a/I3gHl4EJs_lrPfOkVM59HxgrdSa2KZnbcSCWW3KmlVoxtQYBv5_FV2A- | September 25, 2010 at 21:30
What square area does you worm cast control product cover per litre.
Reply - One litre will treat up to 500 sqm per single application. Available from www.thelawnshop.co.uk. Currently selling like hot cakes :0
Posted by: John | September 18, 2010 at 15:03
UNTIL RECENTLY I HAD A VIRTUAL BOWLING GREEN QUALITY LAWN . THE LAWN HAS BEEN INFESTED WITH HUNDREDS OF WORMS FORMING WORMCASTS RESULTING IN MY LAWN BEING DESTROYED.
I HAVE TRIED ALL THE OBVIOUS THINGS. BRUSHING CASTS OFF WITH A STIFF BRUSH, REMOVAL BY HAND & RAKING WITH AN ELECTRIC RAKE(NOT VERY BENEFICIAL TO THE LAWN OVER TIME)
IF CHEMICAL DETERENTS ARE ONLY AVAILABLE TO THE PROFESSIONALS WHAT ON EARTH CAN I DO TO GET RID OF THE PROBLEM.
MY ONCE BEAUTIFUL LAWN IS NOW A SEA OF MUD.
HELP!!!!!!!!!
Reply - We can help by providing a worm cast control product. You can buy 10 litres of it for around £65.00. Email [email protected]. We will have it in 1 litre too. It is not in stock quite yet as only had meeting last Friday but it is good news for domestic lawn owners who can now control worm casts on their lawn.
Posted by: BILL CARRINGTON | September 02, 2010 at 13:15
Please can you help.... One of my lawns which has a wet clay soil has a problem with worm casts. Last year they almost ruined my lawn but a well known lawncare company I used was able to control them with chemicals and it completely eradicated the problem. The worm casts are now returning - I spend about 30 minutes trying to pull each cast off the grass before mowing - but my lawn care company says they are no longer able to use the chemical they applied last year and that it has been withdrawn. Is there anything that they can use or can I obtain the same treatment if I am able to contact a registered professional? Please help before my lawn is ruined!
Reply - We can help by providing a worm cast control product. You can buy 10 litres of it for around £65.00. Email [email protected]. We will have it in 1 litre too. It is not in stock quite yet as only had meeting last Friday but it is good news for domestic lawn owners who can now control worm casts on their lawn.
Posted by: janet lawton | September 01, 2010 at 19:38
Thank you, this information is very helpfull, since I have about 2 years and this years is worse.... evenone i pay for a company call WeedMan in Toronto and they said is group (small animal under ground).
I would like to know what chemical I need to buy or tell them to use to cure my lawn...
thanks...
antonio
[email protected]
Toronto, Ontario
Answer - Antonio - any worm cast chemical will not kill the worms but stop them casting for a 2-3 month period so repeat when there are lots more casts. Normally treat Sept/Oct and again Dec/Jan/Feb. In the UK we use an active ingredient called Carbendazim at 4 lts per Ha.
Posted by: antonio meza | June 19, 2010 at 20:48