Irish Gardeners Forum Home
 FAQFAQ   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Custom Search
Weather Report /
Moon Phase for Ireland

Post new topic   Reply to topic    Irish Gardeners Forum Home -> Irish Lawns and grass care

Lawn Thatch and How to Manage It

Eclipse - The Recessed Manhole Planter
Author Message
James Kilkelly
Rank: Site Admin

Joined: 30 May 2006
Posts: 2142
Location: West of Ireland

PostPosted: Tue Nov 21, 2006 11:47 am    Post subject: Lawn Thatch and How to Manage It Reply with quote

Lawn Thatch and How to Manage It
By Terry Blackburn

Thatch is a dense layer of living and dead organic matter on the soil surface.

Thatch in lawns is often misunderstood; both its cause and control.
Some lawns have serious thatch problems while others do not.
Thatch is a layer of living and dead organic matter that occurs between the green matter and the soil surface.
Excessive thatch (over 1/2 inch thick) creates a favorable environment for pests and disease, an unfavorable growing environment for grass roots, and can interfere with some lawn care practices.

The primary component of thatch is turfgrass stems and roots.
It accumulates as these plant parts buildup faster than they breakdown.
Thatch problems are due to a combination of biological, cultural, and environmental factors.
Cultural practices can have a big impact on thatch.
For example, heavy nitrogen fertilizer applications or overwatering frequently contribute to thatch, because they cause the lawn to grow excessively fast. Avoid overfertilizing and overwatering.
Despite popular belief, short clippings dropped on the lawn after mowing are not the cause of thatch buildup.
Clippings are very high in water content and breakdown rapidly when returned to lawns after mowing, assuming lawns are mowed on a regular basis (not removing more than one-third of the leaf blade)

Photo / pic / image of Lawn Thatch.

Environmental factors typically are another primary case of thatch.
Conditions favoring thatch include heavy, wet soils; alkaline, or high pH soils; and soil compaction.
All are commonly met.

As thatch levels accumulate to greater than 1/2 inch, lawn problems may begin, and the thatch needs to be controlled.
Thatch may be torn out with a dethatcher or vertical mower, but will most likely return unless the cause is corrected.
Mechanical dethatching is also very destructive to the lawn because roots are in thatch instead of soil, so plants tear out easily.
Overseeding is usually required afterwards.
For this reason, it's best to tear out thatch in late August for optimum reseeding timing.

Core aerating helps degrade thatch and also helps solve some of the causes of thatch.

Core aerification, followed by topdressing are two methods that will generally correct the reasons thatch is accumulating.
Core aerifying machines will pull up small soil cores to the surface that are left there to act like topdressing.
The holes created help solve problems such as compaction or poor drainage. Topdressing is simply adding a thin layer(1/8 to 1/4 inch) of compatible soil over the thatch, which adds microorganisms to help in breakdown.

Aerifying equipment may be rented or services are available to do it for hire. Aerifying is an excellent lawn practice with many benefits, as it helps solve soil problems that in turn leads to better root systems and healthier lawns.
Aerify in spring or autumn, making sure adequate moisture exists in the soil.
Make two trips over the lawn, the second perpendicular to the first.
An average of 15 to 20 aeration holes per square foot is suggested.
Cores should remain on the surface and allowed to air dry.
These cores act as topdressing that helps degrade thatch.
Additional topdressing material could be added after core aerifying if desired.

Terry Blackburn. Internet Marketing Consultant, living in South Shields in the North-East of England. Author and Producer of blog Author of "Your Perfect Lawn," a 90 Page eBook devoted to Lawn Preparation, Lawn Care and Maintenance. Find it at

Gardening books. Ireland's allotments.
On Twitter...

Garden Consultation & Design.

Try my Garden Design home study course!
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Irish Gardeners Forum Home -> Irish Lawns and grass care All times are GMT
Page 1 of 1


Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum

Powered by phpBB © 2001, 2005 phpBB Group

Privacy Policy | Copyright © 2006 - 2016 (part of