Home » Why is Thatch the single biggest problem in Bowls Green Maintenance?

Why is Thatch the single biggest problem in Bowls Green Maintenance?

We have had a few queries asking about thatch; actually a few readers asking for a definitive description of thatch and its associated problems, so here it is:

What is it?

Thatch is the name given to the mat of dead roots and shoots that accumulates on the surface of the green. Where moisture, nutrition and cultural practices are optimised for the desired grasses, thatch rarely becomes a problem. However, when soil air content is low, or if drainage is poor and the fertiliser program is not optimised for the prevailing conditions, thatch can become a problem. In severe cases the major root mass might only exist within this layer and this leaves the green susceptible to drying out in summer and to the heads “skinning” (loss of turf cover) in wet weather. Thatch is also a major contributor in the encouragement of fungal pathogens like fusarium and can cause severe outbreaks of disease to occur if left unchecked. Thatch is also a major contributor to localised dry patch problems on greens

What causes thatch?

Thatch and compaction are very closely linked. When the soil becomes overly compacted due to foot and maintenance traffic, oxygen levels within the green reduce significantly. The aerobic (oxygen loving) micro-organisms (soil microbes) within the soil that break down thatch and release nitrogen that can be used by the grass plants to flourish need oxygen to thrive. The microbe population reduces drastically with reduced oxygen supplies.

What can be done?


Physical reduction of thatch is the first step. This can be started during the bowling season by pencil tining to allow more air into the soil and regular verti-cutting to keep lateral growth under control.

You also need to get on to a proper nutritional program which doesn’t use heavy applications of granular fertilisers. Spoon fed bio liquid programs are best as these provide carbohydrate which boosts grass health and increases microbial activity.


Then in autumn you should get serious with the thatch using various methods such as hollow tining and deep, heavy duty scarification (slotting such as Graden).


In winter you need to deep slit tine your green as often as you possibly can when conditions allow (not when it is too wet or when there is frost)

Performance Bowling Greens a practical guide has a full step by step system for improving your bowling green including getting to grips with thatch.


  1. Frank Miall says:

    Dera John thank you for your reply. It was very helpful. My next query is slit tining. I cannot find a self propelled machine on the web and the ones that would do the job all seem to be tractor towed. I have a sisis with chisel tines that penetrate about 4″ will this do instead? I have only been greenkeeper for less than a year and I am having to manage a 7 rink bowling green with just one helper. He’s the only one who can manage the mower!! I spend all my spare time reading articles about bowls greens and find yours very helpful but sometimes not specific enough. Eg. where do I get bio fertiliser with carbohydrates included? Trawling thro’ dozens of web pages is very tiring and the wife complains when I fall asleep at 8pm. Looking foreward to your reply Frank

    • John Quinn says:

      Hi Frank

      Thanks for your message.

      I don’t promote any specific products and I don’t like to generalise…the answers depend on your particular circumstances.

      Liquid bio-fertilisers are fertilisers that contain a high proportion of carbohydrates in addition to traditional mineral elements (NPK). There are many different brands and formulations.

      The main thrust of this site is to try to get bowling green greenkeepers to move away from symptoms management, which frequently leads to an endless cycle of boom and bust in terms of green performance.

      I recommend going back to basics and getting a thorough grounding in what is important and what is not.

      I’ve sent you a little something in an email to help with this.

      Keep the questions coming and I will help as much as I can.



  2. Bob Lemon says:

    Hi. I have just taken over as a green keeper this summer having been a helper for a couple of years. I think I may have a thatch problem but cannot be sure. I scrified heavily just at the start of the season and some bare patches result. I had hoped that these would have shown signs of recovery by now but there is very little. I put some moss-killer on after the scarifying followed by fertilizer when the moss seemed dead. Some moss however seemed to survive. I am spiking frequently. I have put turf tonic on to help with the moss and general welfare? The green is actually running well so I do not want to do anything drastic but the bare brown patches bother me. When I put in a fork into these patches it goes in very easily compared to grassed areas suggesting very little root growth underneath?

    Any suggestions or recommendations would be gratefully received!!


    Bob L

  3. John Quinn says:

    Hi Bob
    Thanks for your message.
    It’s important first of all to establish the level of thatch you have. The best type of sampler for getting a proper look is pictured in this post, but you can use a border spade or similar to cut out a profile section.
    If you’d like to email me some photos of the sample (from a well grassed area) and the bare patches and any other issues such as moss etc, I’ll try to help you further.

  4. Bernard Dowley says:

    Hi John. We are having a problem, we think, with our bowling green contractor who ,as an expert, has a totally differing view of our green than another expert (Lawn Doctor) we brought in to get a report of our green condition. Our contractor has made some statements that the club, as bowlers, don’t understand, so if you could comment that would help us a lot. Two questions:
    1) We have thatch of about 10-15mm in our green immediately below the surface (and thatch fungus) which our contractor says is fine, “it is needed to hold everything together”. From everything I have read this seems nonsense but what degree of thatch, if any, is acceptable?
    2) At the end of last season, we were advised by local people that the contractor only used 3 1/2 bags of top-dressing around the edges of the green, the contractor says they put 40 bags on and as it was brushed in (no tining done before top-dressing) it would disappear, we wouldn’t see it. It that really feasible? I have pictures taken on the day of the top-dressing supposedly done and I can see nothing except around the edges.
    Your comments would be welcome and kept confidential.

    • John Quinn says:

      Hi Bernard
      Thanks for your comment.
      1. 10-15mm isn’t excessively thick thatch, but ideally it would be less than the lower end of this range <10mm. Thatch fungus, however, is a different story and suggests that perhaps the thatch is actually thicker than claimed, best to check yourself.
      2. If these are 25kg bags of dry topdressing compost or sand, it's feasible that it wouldn't be very visible on the surface. 40 bags is only 1 tonne, so if this was spread over a 1300m2 green it would hardly be noticed, especially after brushing in. It might be more noticeable on the edges due to a heavier dressing or thinner grass cover/bare areas?

      Sorry I can't be of more help than this.

  5. john parker says:

    Hi, Our green is ALWAYS very heavy at the start of the season , and continues so for quite a while the maintainance people won”t roll it , surly it needs rolling at least once in march when first growth appears ??

  6. john birtwistle says:


    Our green as had a lot of top dressing for last 20 yrs, now it is solid 1″ down how can we break up that top dressing to let the green breathe,hope you have any ideas.

  7. Brian Glover says:

    Our crown green is wet even late in the afternoon on a dry day…. could this be due to compaction,,… I also note that after heavy rain the green “puddles” more than it used to

    Any suggestions

    • John Quinn says:

      Hi Brian

      It very well could be compaction, but is more likely to be excessive thatch at the surface or a combination of both.

      There’s an article here to help with assessing the situation.

      Feel free to email me some photos and/or questions.


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