QuestionQUESTION: I have an on-going thatch problem. My local extension office (Cornell U.) advises against power-raking or dethatching. I assume they mean heavy raking, not vertical cutting. The Cornell Extension advises treating thatch by aerating with core aerator, which I do...but it doesn't seem to help. I know thatch is not from grass clippings, is caused by imbalance of water, fertililzer, is dead roots, etc.
I seem to have a lot of matted grass after the winter snow melts. My lawn (especially where the thatch is worst) was "tan" much longer than my neighbors. Even after the grass greens up there seems to be a lot of this tan (dead?) matter. I've a few questions:
1) is this matted grass the result of the thatch?
2) does this matted grass become thatch?
3) do you agree with the local cooperative extension office contention that there is no need to rake the lawn in the spring?
ANSWER: Excellent questions, my friend. I'll begin with a few basic tips, but for the real story you will have to answer a few questions, the first of which is: What Grass do you have?
Now you don't have to know the answer, but if you do, it would certainly help.
Second question: I assume you are somewhere in the Northeast? Since you contacted Cornell? But I have to confirm -- Cornell is world famous and you could be growing Grass in Fiji. Please confirm and even better can we narrow this down to a County and State? It helps to know your latitudes and longitudes for Grass purposes. No point going on and on about what it 'might' be, we should figure it out.
And Third - What IS the state of your soil? Please tell me the Cornell advisors have established that your soil is in excellent condition and that Thatch is your problem without a doubt?
OK. Now to your questions.
1. Is this Thatch? Well, I hope you will answer my questions, but we do have to consider the possibility that it is not Thatch. I do need to know what you are growing (some does not produce Thatch). Where you are growing it (to narrow down the list). But we can meantime consider this as a multiple choice question.
Every now and then I quote a paragraph from the Winter Damage To Home Lawns essay at the University of Illinois Cooperative Extension: 'Snow mold damage can also be very visible on many lawns as snows recede in spring. Both gray (Typhula blight) and pink snow mold (Fusarium patch) may occur in northern Illinois. During the wet, cold weather of early spring, snow mold may be highly visible as matted, crusty looking areas. As conditions dry out, snow mold will gradually disappear but infected areas may remain in the form of weak or even dead turf.' Sound familiar? Look familiar? What are the similarities and differences? What do you see out there?
2. Does matted Grass become Thatch?
Let's see where Thatch comes from. There is a very good, clear website that a good fellow named Jim has posted that will tell you All About Thatch (http://www.members.aol.com/groundkprs/Thatch/FindThatch.html): 'We all have looked down on a lawn and seen the blonde laid down blades of grass. Many refer to this as Thatch, but this is not real Thatch...Thatch is a tightly intermingled organic layer of dead and living shoots, stems, and roots that accumulate just above the soil surface.' Jim posts excellent photographs that will help you determine once and for all if you have a Thatch problem or if it's something else. He points out -- and he's totally correct about this -- that 'true Thatch removal is a very destructive process. Ask the southern guys who have to do St Augustine regularly.' St Augustine is a Thatch factory. If you are living in Cool Season Grass territory, Rick, you won't have that Grass and we won't have to address the ways of dealing with St Augustine Grass. If you're growing Zoysia, it's another story. Bluegrass, another story. Please advise.
De-Thatching is a job to undertake when your grass is growing vigorously. That means late spring-early fall scheduling. Most authorities caution us that de-Thatching, in the EARLY Spring, or in very dry weather, does more harm than good, stressing your Lawn.
University of Illinois posts its positions on Thatch Removal: 'An efficient method of thatch removal combines topdressing and core aerification. Allow the soil cores to air dry on the turf surface before crumbling and spreading them with a hand rake, broom, or by dragging a section of weighted chain link fence. Additionally, coring serves to mix soil into Thatch which can also speed Thatch breakdown.'
Provided, of course, that you do have Thatch, which remains to be seen.
You sort of touch on a potential cause of this with your question: 'I know Thatch is not from grass clippings, is caused by imbalance of water, fertilizer, is dead roots, etc.' So you are clearly versed in much, if not all, of this information -- which gives me pretty strong reason to assume you do in fact have Thatch in a cool season grass. There's only one way to get that. Over-fertilizing with SCOTTS! Grub-killing with SCOTTS! Weed-killing with SCOTTS!
Oh No!
Which brings us to question #3. Do I agree that you do not need to Rake a lawn in Spring?
Are you asking this because you do this as a matter of routine?
Totally, you do not need to Rake routinely. Of course, I'll bet Scotts makes a great Power Rake that you can buy at Home Depot for doing this exercise that you do not need to do, but you don't need one. In fact, you should not get one. Because the best thing you can do to eliminate Thatch caused by a Scotts Fertilizer addict is to leave your poor Grass alone.
Fix the soil. Do something about that 'imbalance' -- which I translate to mean 'use of things I should never have used to wreck the balance of Nature around my own house.'
If you DO have Thatch, you should deal with it asap. De-Thatching is a job to undertake when your grass is growing vigorously-- like, NOW.
Very simple.
First, I agree with Lawn Jockey (http://www.lawnjockey.net/dethatch.htm): "The current, and preferred method of de-Thatching a lawn consists of: aeration, organic fertilizing, Liquid Organics applications, or topdressing with compost. Not only is this method more cost effective, it builds a healthy soil that retains nutrients and improves the natural defenses to diseases and pests."
(http://216.109.125.130/search/cache?p=dethatch+organic&tab=Web&ei=UTF-8&fr=my-ve) Take care of that.
Now, Rick, maybe you know, or maybe you don't know. But I'll tell you right here: Chemical Fertilizers and Pesticides lay the foundation for a Thatch problem on Grass not prone to that. Which means: YOU are the cause of your Thatch problem.
OK, I'll bet you are thinking, Why would bug killer or
weed killer or fertilizer cause Thatch? That's the first time I've ever heard anybody say that. That's ridiculous!
So let me tell you how.
Thatch is dead roots and plant material. Those things decompose naturally. They ARE soil. Go out to the Great Plains sometime. Take a good look. See any Thatch? I don't see anybody running through the Appalachian Forest to
de-Thatch the soil. They don't Power Rake the Great Plains in the spring. Right?
But you are considering that you should do that - ROUTINELY!
Why?
Because the tiny, wiggly, microscopic animalcules in your soil that decompose roots and stems are DEAD.
Why?
Think back, Rick. You love your Lawn? You love to stock up on all those Scotts powders and potions and pesticides, herbicides, I'll bet you even had to use fungicides every spring? The 1-2-3 Scotts system?
You kill EVERYTHING in the soil that way. Every time you run through the lawn with a spreader. Those poor, defenseless microbes, they have no chance whatsoever.
You, sir, are the problem. You made the Thatch. And I'll bet it was a LOT of work. You should stop doing that. Then you won't have a Thatch problem.
So, fill me in, here. Tell me what's going on with your Lawn. And if this last scenario is close to the truth, I'll tell you how to stop making Thatch and fix your soil. Intelligently. NOT with Scotts. With Science, sir. The Earth is Round. The Eagle Has Landed. Do you read me? Over.
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QUESTION: Hi:
I tried to reply but you were on break...probably recovering from reading my long email. I am in the champlain Valley (Plattsburgh NY...across lake Champlain from Burlington VT), 20 miles south of Canadian border. So, cool season grasses. I did email the greenskeeper and he said my aerating probably hadn't worked because it needs to be done 4 times a season and probably would take 4 yrs to show a difference. So now I know I don't have to think about raking out that deadish grass in the spring. I will continue to aerate in the fall (can't afford 4 times a year), and will use organic fertilizer. so, my four questions are:
1. I read that compost without first aerating actually makes thatch worse. So, I will use compost topdressing after I aerate around labor day. Does this make sense?
2. Cornell Cooperative Ext says Corn gluten may act as fertilizer but does nothing for crabgrass or annual bluegrass (I have both...especially ABG). I wrote the guy in IA who did the research on gluten. He directed me to a guy at Cornell who never did reply. Do you have any suggestions regarding annual bluegrass?
3. My local Agway sells a product called Milorganite fertilizer. Is this an example of an organic, slow-release fertilizer? If so, can I put this down at this time of year, or do you suggest only fall fertilizing? Since my thatch areas can have developed from overfertilizing, should I not fertilize these areas even with organic?
4. Is there ever anyway to send you email pictures of grass problems?
ANSWER: Plattsburgh -- Postcard country, stunning views, clean air and water, Paradise. What a lucky guy.
I do not know who the greenskeeper is but he could not have possibly told you to aerate 4 times a season? No way. Nope. Impossible. Call Cornell and tell them that. They'll have a good chuckle over that advise. I did. Glad you finally got through, hope it's not too late!
Aerating every 4 years? Maybe that's what he said.
Cornell is giving out some weird advice. Next time you speak with them, find out if they're volunteers -- 'master gardeners' retired from the Post Office, the local school, accountants, senior citizens who meet at the monthly Garden Club. Here's the science on Corn Gluten Meal and what I think they may have meant, if they knew what they were talking about, is that like ALL pre-emergents, Corn Gluten Meal does NOTHING for Weeds or Grass that's growing already but it will stop EVERYTHING from germinating including ALL annual Bluegrass and ALL Crabgrass:
http://www.gluten.iastate.edu/pdf/grnhsechr.pdf
This was a test conducted in 1995 at Iowa State University of how well Corn Gluten Meal keeps 22 weeds from sprouting. They found: 'CGM reduced plant survival, shoot length, and root development of all test species.'
Best results were seen against Black Nightshade, Common Lambsquarters, Creeping Bentgrass, Curly Dock, Purslane, and Redroot Pigweed. Twelve monocotyledonous species tested, including Quackgrass, Large Crabgrass and your Poa annua. The CGM was tested two ways: (1) Mixed into the top 2 1/2 cm of soil and (2) sprinkled over the soil surface, as you would with a spreader.
Velvetleaf and Barnyard Grass were toughest of the Weeds tested.
Researchers observed: "The efficacy of CGM for control of a particular weed ... depends on the amount of CGM applied. Broadleaf species were generally more susceptible to CGM than grasses ..."
The majority of Crabgrass plants are annuals. If you wait, they will be out of commission next year. Remember that as you stare at them this year. Too late for this year, but if you don't let them seed, and you don't let the set seeds germinate, you will hopefully see the last of them. Corn Gluten Meal applied in the spring will stop that from
happening again. CGM is also a great Nitrogen fertilizer and it builds up your soil.
Milorganite is a decent slow-release semi-organic fertilizer that some purists don't like because it has the potential to contain some metals. I contend it's a step in the right direction and I have used it on my soil. It is not as good as Corn Meal Gluten decomposing, because CMG conditions the soil a little better. Milorganite is a nice option right now; it's too late for CMG.
You did not say what Grass you are growing -- did you? I don't see it here. Did I miss it? Just wondering what has built up Thatch.
Thatch needs microorganisms to break down, and Nitrogen fertilizer won't help you there. Slow release Milorganite or CGM take a lot of time, so I don't think this is something you have to hold up or worry about. But you need more organic matter in your soil to get the Thatch broken down. There are 'organic' Thatch breakdown boosters which are basically bacteria and Fungi specialists, and I think it would be a good idea to pick up a bottle of that stuff. You'll find it somewhere in a garden center.
You can send me photos of anything -- I'll be happy to look at them. Send me a private question and I'll give you an email address. Agway has a lot of great, low cost products and it's great you have one where you can buy everything. Maybe they have straight Corn Meal Gluten. Otherwise it's sold as 'Concern Pre-emergent Weed Killer', 'Cock-a-doodle-do Organic Weed Killer' and other things, with the words Corn Meal Gluten on the package somewhere. Don't confuse this with Cornmeal. They are very different. Believe it or not.
Good to hear from you, sorry you had trouble getting through. I was backed up big time in my Questions mailbox and I had to slow down to 1 or 2 a day. I'm freed up now. Please remember to Rate me when you get this -- I would like to shoot for the AllExperts of the Year list at the end of the year, I need a 'Nomination' for that. I'd appreciate it. Thanks for writing, long questions are filled with details and very helful -- Just be ready for a long answer!
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QUESTION: Thanks for the quick reply. First, I am not sure what type of grass I have in the badly thatched areas--sort of a mish mash I think. Regarding the greenskeeper reply. I reread his reply and he said aerate agressively, which he defined as twice a year, 4 passes each time. So, I had remembered that wrong. And he went on to say that he'd had an area of very thick thatch that took 4 years for results...and 8 years later he could still see some remants of the thatch layer when he did core aeration. His reply was actually quite thorough (explaining about the thatch layer, etc.). I believe I found him by following a series of threads from your email...but I may be wrong about that. Anyway, I apologize for misreading and misquoting him.
As regards the corn gluten. When my local extension agent said Cornell did not support the idea of gluten as a weed preventer, I went to the Cornell website and did some searching. Sure enough, there was reference to research done by Cornell around 2000-2001 which had found that the only weed prevention seemed to be from the fertilizing aspect of gluten thickening the grass. Cornell concluded this simply made gluten a very expensive way to fertilize.
Because I knew that the IA research had been done before 2000-2001 I actually emailed the IA researcher, Nick Christians, and asked what the more recent IA research showed. He replied very quickly, but didn't really answer the question. He said I should contact a Professor Rossi at Cornell for his opinion (then Christians added that I could always try the corn gluten on a test patch...and said he thought I would like the results. That didn't exactly answer my question about "recent research at IA" but did seem to suggest maybe conflicting research data. I did email Dr. Rossi at Cornell, where, on the website, he is described as "Mr. Turf" but he turned out to be "Mr. Doesn't Answer Your Email." Anyway, I noted in his on-line resume that he had published research on corn gluten in the early 2000's, so I figure that research is what contradicted Christian's research, and Christian was basically saying, "here, contact the person who challenged my research and then draw your own conclusions."
Sorry for that long tale, but I figured you to be the sort of person who would find this interesting.
Anyway, I plan to aerate this fall and to top dress with compost. Now, this leads to four questions.
1) if I want to put down corn gluten as a annual bluegrass preventer, I understand that the time to do that is in late summer or fall (as opposed to crabgrass preventing in the "while forsythia blooms" part of the spring). But I also understand that aerating should be done in the fall, but early enough for the grass to recover. So.....should I put down corn gluten in, say, late July, and then aerate at the end of September?
2) I have about 100 sq ft to redo in the fall. How do I coordinate that with the corn gluten? Just avoid gluten in those areas? Stagger the timing? What?
3) Should I do some fertilizing right now? If so, corn gluten or Milorganite?
4) When the heads show on my annual bluegrass I stop mulching and start catching my grass (in hopes of cutting down on the reseeding). Is this likely to be at all helpful in getting rid of annual bluegrass, or is something like corn gluten my only hope?
Another time I'll send you pics of some wierd grass that came up where I reseeded this 100 sq feet last fall (Scotts Pure Premium Sunny seed).
Rick
(Left feedback on my other question.)
ANSWER: 'Weird Grass' from the Scotts Pure Premium Seed?
I am no Scotts fan, but I thought their Grass was first rate top drawer state of the art premium hybrid excellent! This is the second remote suggestion that the seed was not up to par. I wonder what's up with that?
Going back to Dr Rossi/Cornell, the guy's probably either on vacation or he's busy growing Grass somewhere and not getting all his emails. I'm impressed that Nick Christians replied to you, and quickly; these are very busy academicians and they don't have a lot of free time. His response to you was also interesting. Sure does look like something is going on behind the scenes.
But we don't care, do we? All we want to know is whether this works or not. I think I'll try a patch of my own, just for the hell of it, now that my peatpots are freed up.
Let's proceed under the assumption that Corn Meal Gluten DOES work as a pre-emergent.
Problems: (1) You have Weeds, and (2) you have Thatch, and (3) you don't know what Grass you are growing.
Your soil is part of several problems.
1. You have to find out what Grass you have. Take it over the a local Cornell office and get them to i.d. it. I want to know if you are growing Zoysia -- the Grass that does not green up until late in the spring. Zoysia tends to thatch up. That's different from a Thatch problem in a Bluegrass Lawn. This is easier than wiping out your Lawn and starting from scratch.
2. Get yourself a soil test. I thought I read that somewhere along the way, but I do not see any reference to that now. Cornell does a good one for a modest fee.
3. If you are catching the Grass clippings to remove Poa annua seedheads, put down a bag of Milorganite to make up for it.
4. Plug aerate your Lawn to get Oxygen into the soil. Compact soil needs Oxygen because Aerobic microorganisms need Oxygen. But the soil is barren of Aerobic microorganisms. Compost meanwhile is one great big microorganism factory. After you aerate, apply Compost and/or other Organic Matter. You have GOT to raise the Organic Matter in that soil.
Thanks for your feedback -- we should keep these threads manageable for AllExperts. I have your emails copied and I refer to them to stay on track. Keep me posted and I'll look further for the CMG testing/trashing.
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QUESTION: The grass is either bluegrass or perennial rye (I don't think it's fescue). Definitely not zoysia. (In recent years I've developed some patches of creeping bent--usually where the water runs off the sloped thatchy areas and gets/stays wet where it levels off--and creeping bent develops there. The soil PH was right in the neutral zone. I've sent samples of grass to Cornell, but usually get rather vague answers...some of this, some of that...but always cool season grasses. Thatch: when I core (or if I dig down), I get 3/4 inch to inch (maybe a little more) of thatch in the areas that are sloped and are over a lot of sand backfill. I think the soil is basically pretty crappy (but I grew up in Minnesota where my dad's lawn was on Red River bottom ).
I operate on the assumption that aerating should be done in early fall so that the lawn has a good chance to recover. I assume I should not core aerate this time of year.
AnswerYou can core aerate in spring or fall, but we're about to enter summer -- so I'm with you, aerate in the fall.
One of the Grasses should dominate after a while. Thanks Heavens you don't have Zoysia. That would be something to worry about.
Why do YOU think your Grass developed a Thatch problem, Rick? You have a theory on this, no?
