Mike McGrath - Hatred of Shredded Bark Mulch

I listen to podcasts of "You Bet Your Garden" hosted by Mike McGrath who was formerly associated with Organic Gardening magazine. He seems to display a visceral hatred of shredded bark mulch products - especially those manufactured from reclaimed shipping pallet "waste." He accuses them of causing all sorts of problems including shotgun or artillery fungus (damaging to house siding) as well as detrimental effects on plants & soil life. Does he have a valid point or is he blowing things all out proportion? I would love to be able to mulch all my beds with yard-waste compost but finances & availability do not make this a realistic option. Any thoughts?

I haven't heard this. I usually use gravel mulch, or compost - but when I need something in between, I use shredded bark/wood products. I prefer "shredded" because it stays put in wind and rain better than nuggets. Organic amendments are very variable. They are different between suppliers, between years, and sometimes beween bags from the same supplier the same year. Yes, I would believe one could bring just about anything in with any organic amendment. However, I don't have enough stuff in my own yard to make enough mulch and compost for the rest of my yard, so I buy the stuff. Was he concerned about treated wood? I would assume that pallets would be made from cheap untreated wood, and be fairly disease free - a pallet would seem a poor host for a disease.

Shipping pallets wouldn't have any bark on them, so while I can understand his concern about wood that came from them (might be contaminated with chemicals, etc if things got spilled on them, etc) I don't know how he's making a link from shipping pallets to bark mulch since there's no way to get shredded bark mulch from a shipping pallet. Wood chips yes, but not shredded bark. If you're trying to garden as organically as possible I'd probably stay away from the bark mulch that's been dyed red, black etc and stick with bark that's its natural color but I don't see why it would cause a problem for your soil.

INgardener, yep, McGrath loves to extol on the bad sides of wood mulch, mainly discussing artillery fungus and also nitrogen depletion. I'm hearing more about the fungus in the past few years mainly in articles and University documents, most likely because of the extensive use of chipped/shredded wood as a mulch. So far I've not heard of it happening to any of my customers (yet!).

The nitrogen depletion (or tie-up) is a given for just about any organic mulch/amendment. This usually has a greater effect on plants when it is worked directly into the soil though, where it robs the root system. Wood mulch that is on top of the soil won't steal nitrogen from the root system of plants as there is only a slim layer of it on the surface, not underground. McGrath has recently begun recommending compost as a mulch but I don't think I'll ever have THAT much compost readily available.

Shoe (off to market, it's Trick or Treat Day!)

Maybe I should have been more precise in my wording and will also have to re-listen to one of his diatribes. He's definitely against dyed mulch products and he may have more of an issue with wood mulch per se (not derived from bark) than with shredded bark mulch. He doesn't like mulches derived from ground shipping pallets which I can understand. They may have been made with fumigated wood products.

But I do think that mulching all your garden beds in truckloads of compost is overkill and a waste of money. I treat my compost as "black gold" and apply it fairly selectively - just because it takes so long to manufacture. Out here, they charge $32 a cubic yard for compost. Truckloads would cost hundreds of dollars.

I hear ya on the compost issue, I've never had enough to use as "mulch". I think if you could spread two inches of it on your garden bed (or around plants) it would certainly be of benefit but I prefer to mix it with the soil as it goes much further. Either that or use it for making compost leach/teas.

Shoe

A point to remember about using mulch made from chopped up wood pallets is that it is termite food! Trees have bark to keep out insects, including termites, so shredded or chopped bark mulch is great and isn't much of a "nitrogen-stealer'. Wood-based mulch from pallets is a whole 'nother story! Using wood pallet-based mulch is like setting out a buffet for termites. Also, using utility line crew tree trimmings (that are often offered to homeowners for free) gives you the same problem. I have some friends who a few years ago had thousands of $$$ of damage to their home from huge termite colonies living in the ground under "mulch" they got free from the electric company crew that had trimmed trees in the neighborhood. They showed me the termites when they called me to identify the "bugs" in their mulch. Raking back the ground-up trimmings uncovered thousands of termites! Unfortunately, the termites had already gotten into their foundation.

Last year, a local trash collection business sold "mulch" made from all types of wood products, mostly wood pallets. By the end of the summer, they were getting a tremendous amount of complaints from homeowners that shrubs, perennials, and annuals were dying in beds mulched with their mulch. Seems there were all sorts of substances in the pallets and other wood scraps used for the mulch, including gasoline, kerosene, paint thinner, and more. They don't offer that mulch this year!

I wonder if mulching up to the foundation is facilitated the termites. Definitely you wouldn't want any organic matter in contact with wood, and usually folks say leave 4-6 inches even of concrete bare (so you can see right away if they start building their tubes) up the side of the house, and a foot or soil of dry soil going out from the house.

I'd sure stay away from used pallets. There's just no telling what spilled and soaked into them. But we have real good results with appropriate use of ground tree trimmings. (Plus if they're a local source you don't have the environmental impact of trucking the mulch around the country.)

I agree, most definitely, that proper use of ground tree trimmings is a good thing. I just wouldn't use them anywhere near a house foundation.

Amen, keep the wood away from the house. I use cedar mulch, and only sparingly, near the house. And they can come in underground in cracks, (my 30 plus house must have a few!) so I question the keep the wall bare thing that we are told.
Last time I used regular cheap shred wood mulch, it rots so fast it probably is cost effective to use better stuff anyway

aren't a lot of wood pallets treated with chemicals? I would stay away from them all together if there is no way of knowing which have and haven't been.

The last time I used wood mulch I had a huge problem with spider mites. Don't know if maybe they were attracted to it or what. Now I use unsifted compost from my pile.

Momherb

I've never heard of mulch contributing to spider mites--I suspect that may have just been a coincidence. I use mulch all over my garden and the spider mites all stick to the container plants that don't have any mulch.

My many beds are now well over thirty years under continous ground wood mulch. I keep an average of two to three inches in place all the time. My cleanest source is a professional tree trimming and remmoval firm. Twice ground minimum load of five yards at $20.00 a yard is delivered free. I choose to use new wood. It simply remains mulch longer.

Here in the Northeast nearly all pallets are treated and should not be used. I am reasonably sure the only weeds we have are delivered by the birds. On finding good clean ground wood the buyer must do the homework. Most suppliers now grind anything they can get.

As the use of compressed waste wood pellets for heating grows the price of wood mulch will have to go up and or the wood mulch supply will cease to be on the market. I can no longer get sawmill sawdust for this reason.

When they make pellets out of green wood they get a pesty liquor and menthane. An effective use has not been worked out but both products can be used and will be in time.

Twenty five years ago I worked with a firm named Sprout Waldren where in we made wood pellets out of waste paper for a plant that had seven tons a day paper waste. In the process we got menthane. We fed it directly back to the boilers in the form of gas. That project was ahead of its time. Today they either use all the pellets they produce or easily sell them. Our company modified the natural gas burners to burn menthane and the materials handling eqipment to transport the gas and the pellets to point of use. The pellets were burnt in high pressure coal fired boilers.

I really liked dear old Ruth Stout who said.....if you read more than one garden book or magazine you are already in trouble. As to mulch in gardening she just piled it high and deep with whatever she could get. In her time I doubt that pallets were treated. Now many are.....yet your wood grinders take and grind anything they can get.

All the way up through this thread is the usual fear factor spewed forth by one writer or another. Folks those writers are pushing lead to make a living. They have to find all kinds of thoughts to cover paper month after month. Then there are the challenges from you and I many without thought or concern for fact.

That's just the way it has always been back on the farm so to speak. I suggest you get just one good organic basic book you like and throw all the rest in the hopper. Stick to this plan and you will build healthy good soil without fail.

You are soil building and may do so by simply following nature who does all the time what one writer or another deems horrific. To make a point nature puts every broken limb on top of the ground. In fact come to think of it just what and how does mother get nutrients back into the soil? She does not have a tiller does she? When one of her members gets sick she sends out her kill team to end it all as soon as possible and lays this too on the ground to be consumed and reused by the local biology.

I feel we all need to be less dependent on garbage gardening talk and just go back to the basics. Biology will take care of itself if we but provide it with mixed basic elements to work on.

The basics are simply: Manures, compost, mineralization, mulches and cover crops. Mycorrhizae may fit in there too but that is really just about the entire story.....in so much as we can do to help mother nature.

There is an exception to every rule. My yard in border-line high in salt - the native vegetation was salt-tolerant stuff. If I want to grow veggies, I have to be careful about adding anything that might add salt. The salt content of manure can be anywhere from low to high - so no manure here.

I think that Eliot Coleman is one of the great authors out there. He talks in great detail about soil and what should go into it.

Eliot Coleman has been doing right and good things for many years. One could hardly do any wrong following his principles. He is getting up in years. Enjoy him while you can.

I agree. He believes in farming from the ground up. He doesn't treat problems and actually prevents and corrects what is causing them. I hope to meet him in the near future.

I think he is right about not using wood mulch. There isn't anything natural about it unless you are growing woodland plants. Lots of people are all for mulch, but I have found that the bigger your garden, the less possible lots of mulch is. It just becomes financially absurd, and even if you got it free, it would require an enormous amount of work to spread it all over a large garden. Re palettes, they are notorious for being the means for pestiferous foreign bugs to get into a country. So I would say they are out for that reason alone, and, as someone else mentioned, that they are more and more made of treated wood. Nobody wants that poison in their soil.

My goodness now I just learned that pulling tons of weeds and applying gallons of water that evaporates from unmulched soil is more natural and less expensive than maintain a decent mulch.
Somehow that does not work into my thinking at all. Never has and never will. My friend I say if you can not afford proper care close down gardens to the point of making better management possible.

Almost all natural plant communities exist with some sort of permanent "mulch" situation, be it leaf litter in the forest, dead grass on the prairies, or even rocks in alpine environment. It's humans who try to maintain landscapes and gardens without mulch, which to my thinking is "unnatural". However, paraclesus is correct that it can be difficult to obtain (either free or for money) enough mulch for a large garden, and it is work to spread. Personally, I regard using mulch as a good thing for the soil and the work spreading it is exercise, which I really need every spring. Mulch is an investment in improving the soil, while conserving water and definitely eliminating a lot of work spent weeding!

To each his own though. There's more than one way to skin a cat, etc.

Elmira, NY is dead center in the great Appalachian Mountain chain. Clean hardwoods are not at all difficult to locate. Professional tree trimmers "usually" have the clean ground wood. The buyer needs only to nicely ask or visit the site and observe. I live one hour South of Elmira. Our cost for six cubic yards delivered this year was $120.00 for twice ground. It takes my two helpers two short man days to put it into the beds three inches deep. This application lasts for two or more years. My beds have been under permanent ground wood mulch undisturbed for just short of forty years. Sure a few replacement or change plants got dug in and mulched the day of planting. My weeds are 99% delivered unto me by my feathered friends.

Wow! Such a bargain! Here, six yds. of twice-ground hardwood (bark) mulch, delivered, would cost at least twice that amount. We can get an "environmental" mix that is more wood than bark for somewhat less.

I cannot imagine spending $120.00 a year for trucked-in mulch. It just seems crazy to me when I can buy a few pounds of white clover seed for about five dollars and grow a crop to either till in or leave as a living mulch. And it is a lot easier to broadcast white clover seed than spread mulch.

I speak of our foundation and flower beds while I think our Elmira poster is refering to food plot beds in which case ground wood would not be desirable or cost effective.

docpipe: Your gardens look like a beautiful personal Eden. I'm sure they have given you many years of enjoyment and reward. Here's to a great gardening year in 2010!

Thank you. I've been working this property for nearly forty years. There has never been soil that saw the light of day more than a few hours. Organic healthy soil principles have always been practiced here. I retired the food plots over the past two years as my health demanded.

That's true--I am talking about food plots when I describe using white clover for a living mulch or for a green manure. For perennials, the ones I grow prefer shade, so I just rake up leaves around them if they aren't already there (which they generally are) or I allow creeping charlie to grow around it as a ground cover. If it's a woody perennial, seems to do fine with creeping charlie.

We have on site maple leaves but not nearly enough. I grind them down so they will lock up and not blow away but they break down and move into the top couple inches of soil in one year's time. Our township has free leaf piles of various ages. They will load a trailer or truck for six dollars. At my age that is a welcome service. At least one of my books states that leaf mulch when broken down into humus is not that far away from composted manure values. I really believe the worm cast returns are far more valued than any NPK figures one might post. In the long and short of all the written words the bottom line is that anything that rots ends up the same literally negating which is better. The only difference ends up being the time it takes an item to completely convert into humus.

As one once wrote the words of wisdom....."count the worms and worry not about to much else". My best year ever was one that provided a twelve to fifteen adult worm count per turned shovel full of the top five inches in the prime worm counting period. My organic material percentage in the soil was 17% that year. That year the worms were eating and or taking down five to six five gallon buckets full of coffee grounds every other day.....sometimes in a single day. The patch size was approximately 1000 sq. feet. That patch was mulched with spoiled hay. The crop was one pumpkin plant growing one nearly 900 lb. pumpkin. It was a nice pumpkin but not into bragging size at all. At that time 1300 lbs. turned heads. Today it takes over 1700 lbs. to win nationally. I no longer grow but you should see the grass and white clover growing where that patch existed. I tried to find an interested gardener to share crop that patch. No one responded to my offer.

Well, if I were nearer you, I might take you up on that patch! But I know I will have more than I can handle this year with starting so many perennial herbs. Our city keeps talking about their compost program, but when I have called them to see about actually getting some, they say it is not ready yet. The prison kitchen was supposed to have one too, but I call them and no one has any idea what I am talking about. So I gave up on that and was resigned to driving up to Agway in Ithaca with a rented truck to get compost, which just seems totally nuts to me, not in any way sustainable. Then I decided to try out using clover instead. I was partly inspired by stuff I read and partly by my neighbor, who is a very elderly, avid gardener and although he does a lot of stuff I would never do, like spray with Sevin preventatively(!), he also grows annual rye every year and tills it under. He has no worms because he tills as a way of cultivating and his tiller goes 8" deep (I till maybe a couple times a year 3" deep; I have tons of worms). But he inspired me to try not rye but white clover, because I knew it would feed the bees and it's nitrogen fixing too. It's been a real boon and I plan on experimenting with it some more. One of these days I would like to have enough land for growing that I can try out a three-year rotation of green manure. This is supposed to get you to the point where you need almost no external inputs. I would love that. Meanwhile, I do what I can with my city lot.

Your work plans sound real good. Like the fact you are using clover. I never had enough nerve to try clover this far North. Rye was my choice. The two things I do not think you mentioned are trace minerals and Mycorrhizae. My patch was 1000 sq. ft. For trace minerals I used ten pounds of each both Spring and Fall.

I have never had anything but success placing raw manures just ahead of the fall cover crop. I tilled by segments about three weeks ahead of planting in the spring. Some years I mulched most of my plantings with leaves and or spoiled hay. That of course went into the soil in the fall prep including more leaves.
My goal was to get above fifteen percent organic matter in the soil to grow even larger than 900 lb. pumpkins. If we got an early spring I often added a little more manure in the spring ahead of the tilling. Two years ago when I closed the garden the organic material was at seventeen percent. The top soil structure was right and then my health became an issue.

Please note this was the soil building time period. The object was for maximum conditioned biology and fertilizer content to grow giant pumpkins. I paid no attention what so ever to the usual NPK. We kept a PH 7. The farm agent took one look at my test results and declared his ignorance claiming I had ruined my soil. I quickly determined he was not on my team. LOL Truth is he did not have the foggiest idea how to build soil organically and used his 10 -10- 10 Round Up and other poisons as a cure all.

The clover seed I get is rhizo-coated, but I was reading Paul Stamet's book Mycelium Running, and he has a little section on using mycorrhizae for veggies other than legumes. I looked around but could not find anywhere selling the stuff. He said there were different strains for different veggies. Is that what you tried? Where did you get it?

There are two major types of Mycorrhizae. They are Endo and Ecto. The Endo types are for your gardens while the Ecto are for foundation plantings, trees and shrubs. I found it the last two years in small five pound packages at Lowe's in our community. If you use a Google search you will find numerous mail order sources.

Most retail products do not break it down for specific veggies other than legumes. In fact most retail products include what the legumes need in the Endo types. Some retail offerings have both types in one product. This will not hurt anything but it is just wasting one half of the mix.

There is excellent reading and product for large users at: Bio-Organics.com. The archive of monthly newsletters are priceless on this site.