Question
QUESTION: I have St Augistine grass and would like to dethatch it. I have been told there is an attachment I could buy for my lawnmower. Is there such a thing?

ANSWER: The best work is achieved with a de-thatcher with blades or tines.  Thick thatch layers are most effectively removed with Sod cutters, but these all remove large amounts of live Grass.  Rake-type de-thatchers do not get very good reviews.  Spring-tine models that attach to Rotary Mower blades are not just ineffective -- they MAY actually DAMAGE YOUR LAWNMOWER.

Dethatching machines go by several names.  They are variously known as 'Vertical Mowers'.  'Verticutters'.  'Power Rakes'.  'De-thatchers'.

Authorities warn of the perils of de-thatching: Never de-thatch wet Grass.  Never try to finish in a single treatment an entire de-thatching project.  Never de-thatch unless your Grass really needs it; this is not something you should plan on doing, say, every Spring.  People who have a Thatch problem usually cause it themselves, by over-fertilizing with Nitrogen.

That said, St Augustine and Zoysia are the Grasses that benefit most from a de-thatching treatment.  And June is the best time of year to do that, because those Grasses grow full speed ahead at this time of year.

Among the moderately priced retailers, Outsidepride, a highly esteemed Organic Supplies and Equipment retailer, sells a 48" BRINLY unit made by the Brinly-Hardy Company for towing behind the lawnmower:

http://www.outsidepride.com/store/home.php

Jack's Small Engines sells several others from Brinly-Hardy:

http://www.jackssmallengines.com/brinly_dethatchers.CFM

'The patented BRINLY Dethatcher gently combs thatch and clippings to the surface where they're easily bagged or re-mulched.'

Keep in mind when looking for one of these the warning posted at the Garden Equipment 101 website: 'If you are going to purchase a de-thatcher, beware of cheap units with tines made of weak alloys.'
(http://www.gardenequipment101.com/lawn-mowers/lawn-dethatchers.aspx)

De-thatchers are easy to rent at garden centers.

But I have to warn you, most informed lawnspeople agree that even a St Augustine Lawn has to be in VERY sorry shape to deserve a de-thatching treatment.  This Grass has a lot of major parts exposed above the soil surface; when you start amputating, there will be very little left of much of your healthiest Grass.  Think about this carefully.  If you'd like to discuss alternatives, let me know.  Remember, I know a lot of greenspeople and retired scientists who can collectively give you some great insight into this problem.  I'm happy to help.  Thanks meantime for writing.

---------- FOLLOW-UP ----------

QUESTION: What other options are there? I have thatch, I have to dethacth. What choice do I have.

Answer
A certain amount of Thatch is normal.  St Augustine Grass has deep roots, but it spreads with surface runners -- stolons -- OVER the soil. Your climate can be brutal in the Summer; Thatch is a natural, moisture-protecting mulch, blocking the hottest rays of the Sun in the hottest times of the year from baking soil and the roots that grow in them.  Thatch also protects your Lawn from invading Weeds, blocking seeds from making contact with the soil.  And Thatch contributes Nitrogen and other minerals to your soil as it breaks down and decays.  DO YOU HAVE A THATCH 'PROBLEM', SIR?  Or do you have a normal, desirable Thatch layer?

What is problem Thatch?

When it starts to build up and is more than 1/2 inch deep, Thatch ceases to be a desirable situation.

Thatch is a dense net made of Grass stems, both alive and dead, plus blades and roots.  It is broken down under normal conditions by microbes in your soil.  Microbes like Fungi and Bacteria and Protozoa.  Yes, even Fungi are desirable.  And in a normal, natural Lawn, Fungi and their spores are down there all the time, dormant when conditions are not Fungus-friendly.  Ditto, Bacteria.  Protozoa, I'm not sure about.

Some people would pick up the Power Rake at the first sign of Thatch.  This is first degree murder when you are looking at only 3/4ths of an inch of Thatch.  St Augustine Grass is more drought tolerant than people give it credit for -- but not if the above-ground stolons are exposed and dry out.  Plenty of roots from your St Augustine Grass are growing in the Thatch layer.  A Power Rake will yank up the whole plant and crown.  There goes all the moisture protection.  All the new growth in your St Augustine sprouts out of the stems.  Once they're dried up, that plant can't grow any more blades or roots or stems.  Adios, St Augustine.

If your Thatch is deeper than that, Core Aerate.  You can do that right now.  It enhances Water and Air flow, it opens the door for nutrients, it makes your Grass AND your microbes happy!  Aerating will contribute to soil correction   by relieving compaction and breaking up that Thatch that you are targeting.  Mowing correctly -- and KEEPING THOSE CLIPPINGS ON THE LAWN -- will enhance the protection that your Thatch layer offers.

Climates where there are LOW levels of Rain tend to have LOW microbe populations.  Add heat to that equation and it gets worse.  If you can raise the number of microbes -- which for some species will be at this point ZERO if you have used even one dose of chemical fertilizers or pesticides or fungicides -- you will have automatic Lawn Thatching without lifting a finger.

I need more information to help you with that.  If you tell me where you live -- the State and your Zone, or best of all your Zipcode -- I can give you further details.

I KNOW you're not going to be sold on this concept in 2 simple e-mails, my friend.  But while you're shaking your head in frustration, give it some thought.  And send me your info.  I'll give you the simple steps.  They won't break the bank, and I GUARANTEE they will work.

Even if you DON'T have a Thatch 'problem'.

Meantime, see the Better Lawn and Grass Institute's website for a friendly guide to 'Mowing, Fertilizing and Watering your St Augustine Grass': http://www.turfgrasssod.org/lawninstitute/homelawn_programs.htm.