# Organic matter %



## Grassmasterwilson (Jun 11, 2018)

I'm curious where you like your organic matter to be? Most of mine are below 2% and under 1% is not unheard of.

Top dressing is not done here and even with the investment of equipment funding good compost and the client to pay for it is probably unrealistic.

I've added humic acid to my program and should get 3 gallons per acre of a 12% humic product down over multiple apps.

Is there another way? Anyone do a stand alone soil app?


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## Ridgerunner (May 16, 2017)

@osuturfman abd @viva_oldtrafford I believe are golf course superintendents and could speak to that topic but I'm guessing you're question is more directed at the professional lawn care service perspective. That would be @thegrassfactor and @Greendoc . There may be others lurking.
I'm always good for an unsolicited opinion if needed. 
And Welcome to TLF!


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## g-man (Jun 15, 2017)

I would like mine at 5% but it will take years and a ton of material. I dont believe any liquid product will replace some real organic material (compost). I like to aerate and then try to backfill the holes with compost.


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## Mightyquinn (Jan 31, 2017)

I prefer 0% as it seems to create more problems than it solves for me  YMMV :thumbup:


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## Suburban Jungle Life (Mar 1, 2018)

I would think it depends on what you want from your soil and grass. If you want a golf surface to walk on and not compress, probably 1% or less. They also fert and apply stuff often so there isn't a need for slow release anything I guess. For golf, they also don't want the water retention of a high % since they can just water anyway as needed. On a home lawn, a higher % would retain nutrients and act as a slow release mechanism provided it is high enough. In clay, you have such high CEC so maybe a high % isn't that desirable but then again, om might allow better drainage than clay. Perhaps 3% in clay might be fine. In sand, since everything drains right through, maybe a high % like 10% might be more desirable. Really more so as a substitute for the lack of silt and clay. It can retain nutrients and water longer. Granted, at some point this will create other problems if it is too high.
If you are trying to increase om, I'm betting root cycling is probably the best way. A well fertilized and maintained stand will grow more roots allowing more roots to die every year and add that desired om. If you want a super flat lawn, high om might not be the best thing especially if it keeps decaying and leaving uneven ground. Too many things to think about but unless you have sand as your growing medium, I'm not sure a super high om is needed. It can help extend release of fert but you can use slow release fert or fert more often to compensate. Except, if you live in FL with months of fert blackout dates...
Food for thought. I'm sure others will chime in with expert opinions and hard facts.


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## Delmarva Keith (May 12, 2018)

Grassmasterwilson said:


> I'm curious where you like your organic matter to be? Most of mine are below 2% and under 1% is not unheard of.
> 
> Top dressing is not done here and even with the investment of equipment funding good compost and the client to pay for it is probably unrealistic.
> 
> ...


My first question would be why you want to increase OM. Is there some specific issue you are dealing with? As others have already said, you need a lot of added OM to move the needle even slightly on soil %. Natural root cycling effects over the long haul are a lot more practical. If CEC is low, just take that into account in your fert scheduling and dosage.

One situation where I have seen added OM make an actual visible difference is establishment. Very aggressive aeration, spread compost and seed has produced a more vigorous early stand than just aggressive aeration and seed. Over time, the differences lessen and unless there was some specific soil issue the added OM was intended to deal with, by a year in you can't tell any difference.

I don't have any experience with the new miracle elixirs. I'm waiting for the early adopters to take the arrows or find the gold.  The probiotics angle makes sense but all the miracle concoctions would still need tons of raw material to process. Even if it speeds up the overall process two fold (unlikely) so like ten years of regular apps of concoctions versus twenty years without. I guess it has to start somewhere. :mrgreen:


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## viva_oldtrafford (Apr 4, 2018)

Can answer in depth later, but we look for OM below 3%. Higher than 3% has been proven to inhibit root development (water held higher in the profile), creates anaerobic conditions (wetter soils compact easier), hold water (creating softer conditions). OM is negatively charged, so when it holds water(adhesive water) it holds it tightly (water is polar) - it holds it so tightly that we consider it to be hygroscopic (cannot use it). We can use the cohesive water (water attaching to hygroscopic water). I dislike excess OM, but homeowners may be ok with higher amounts.

I use OM enriched sand to increser my CEC, but im also trying a humic acid product on a fairway with a cec of 2.


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## Green (Dec 24, 2017)

Mine is around 5% in a naturally sandy soil that's becoming more of a loam over time...supposedly that's considered pretty optimal by many. It's gone up slightly over the past 5+ years. Where I live, having a decent amount of OM is helpful because we get a hot and moderately humid July and August (mid 80s up to the low 100s at times with dewpoints in the 70s) and cold Winters (down to -5F or lower almost every year). In the heat, the OM helps hold water and buffer the release of nutrients. In the Winter, it helps prevent leaching I guess. Between Winter dormancy and Summer stress, we're in recovery mode for a good amount of the lawn season. And we have a lot of rocks in our soil, so the roots will never be two or three feet deep. The joke is, anywhere you dig, you're likely to find a rock, and it's true. The OM helps hold everything together and compensate for lack of deep rooting due to rocks.


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## Ware (Jan 28, 2017)

I don't chase OM numbers. My last two tests came back in the 1.6-1.8% range and my bermuda seems to be doing just fine.


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## g-man (Jun 15, 2017)

@Ware to be fair, Bermuda doesn't even need soil. It will grow on concrete as long as there is no shade. :lol:

Our wimpy cool season lawns need all the help that they could get to survive the summer and winters. Green's rational is spot on for a homeowner of a cool season lawn, in my opinion. My soil is mostly clay with a lot of calcium, if I let it dry it becomes a brick but the OM helps it.


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## Butter (Nov 14, 2017)

I always thought more OM was better. Like Green, I have brutal summers and mostly brutal winters. Seems like OM is good.


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## Ware (Jan 28, 2017)

g-man said:


> Ware to be fair, Bermuda doesn't even need soil. It will grow on concrete as long as there is no shade. :lol:


Yes, if you can grow fingernails you can grow bermuda. :bandit:


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## kur1j (Jul 2, 2017)

What is done to alter your OM %?


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## Turfguy93 (Aug 30, 2017)

With more organic matter the more you have to worry about 1 water infiltration 2 holding too much water 3 nitrogen releasing when you don't want it to 4 reduced root growth 5 softer surface. You can grow great turf with little organic matter


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## Delmarva Keith (May 12, 2018)

Butter said:


> I always thought more OM was better. Like Green, I have brutal summers and mostly brutal winters. Seems like OM is good.


OM is good. Among other things, it's like a bank of fert in the soil, can improve soil texture, etc, etc. But like Ware says, there's no point chasing OM numbers trying to add OM to existing turf in low OM soil. You just need too much of it and it has to be worked in. To much pain for not enough gain.

Golf courses try to minimize OM on greens and high value turf areas. I don't maintain golf courses - too much work 

A practical goal is to increase OM over time. All this means is keeping the turf healthy for root cycling and to mulch clippings back into the turf instead of bagging so there's no removal of crop stover.

The only times I can think that I've added OM to soil (actually worked it in) was for some really hard packed sandy clay right by the coast that just would not take a drop of water (think like thousands of cubic feet of a material the texture of solid chalk and dry as dust under the surface to as far down as you cared to dig), or for establishmemt of a new lawn (does seem to help with early stand vigor, but probably not enough to make the cost worthwhile). A pretty consistent rule of thumb is If a site has anything at all growing on it, the soil is sufficient to grow grass. Might need plenty of fert, might need extra water in the early years, but turf will grow and growing healthy turf will improve the soil.


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## Grassmasterwilson (Jun 11, 2018)

Was just taking the next step in development of my residential program. All lawns are getting proper fertilization and if allowed corrected(lime and K) with a soil test. I still have a few not responding as I liked and noticed CEC and OM were low.

Here are 3 in question. The 5.5 pH has been corrected as well as the potassium values.

Most all soil test are similar. I know my K is low and I have corrected within the program. Most all numbers are at or above the MLSN


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## Delmarva Keith (May 12, 2018)

Grassmasterwilson said:


> Was just taking the next step in development of my residential program. All lawns are getting proper fertilization and if allowed corrected(lime and K) with a soil test. I still have a few not responding as I liked and noticed CEC and OM were low.
> 
> Here are 3 in question. The 5.5 pH has been corrected as well as the potassium values.
> 
> Most all soil test are similar. I know my K is low and I have corrected within the program. Most all numbers are at or above the MLSN


A general rule of thumb is to multiply CEC by ten and that is the rough cation "holding" capacity of the soil in pounds per acre. So for the low CEC sites, it may well be that the water soluble positively charged nutrients are used as needed and then the excess leached out of the rootzone in a relatively short time, leading to deficiencies even though "enough" was there or was applied.

So taking K as an example, you have to figure out the crop need and then make sure it gets supplemented within the time it persists based on the CEC and crop use. To simplify, spoon feed your low CEC sites more frequently and see if you get positive crop response. If so, you know there was a deficiency. Use that info to maintain the site going forward.

Also, my recollection is the MLSN numbers were derived based on pretty "ideal" conditions (golf course sites with golf course levels of care). The best true test remains crop response (or actually crop tissue tests but nobody ever does that on a lawn so I always forget that one). Like more highly stressed turf may need more K, for example, even if the same turf maintained on a golf course would be fine with a bit less K.


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