Pah-leese...

This is exactly the kind of fear mongering that embarrasses anyone who values research-based information -- the bulwark of Master Gardening. This is a very old story that has been around for well over a decade. As with anything (like table salt), a product used improperly or in the wrong situation can cause problems.

And where, exactly, can I find the research on these laughable pH assertions?

We need more research; not more emotional crusades.

IronBelly

Yes, I'd agree this issue has taken on more of the aspect of an urban legend than one with scientific merit supporting it. First, not all cocoa bean hulls are created equally - it is the chemical theobromine which provides the toxicity. This is concentrated in dark or baker's chocolate (canines would have to consume a significant quantity of milk chocolate to incur anything more than an upset stomach - it's not good for them but certainly not poisonous) and can be of significant presence in cocoa bean hulls UNLESS the hulls have been thoroughly dried. The oil is dissipated in the drying process and thoroughly dried hulls should contain little if any theobromine and therefore pose minimal threat to animals.

Second, the chocolately aroma which is attractive to pets and kids also dissipates rapidly. No scent = very little attraction.

Third, cocoa hulls have a pH of 5.8. A bit on the acidic side, making them a good mulch to use with ericaceous plants. Soils have a buffering capacity that resist significant changes in pH - more in clay soils, less so in sandy soils. One would have to apply a considerable quantity of cocoa hulls AND incorporate them well into the soil to alter soil chemistry to any significant degree. And the effect would be only temporary at best. When used as a mulch or top dressing the effect on soil pH is minimal. NPK is 2.5-1-3, so unlike wood mulches, does not affect nitrogen availability. I'd be cautious about using this mulch heavily around plants which have a phosphorus aversion, however.

In short, they make an excellent organic and soil improving mulch and have an additional benefit of being a slug deterrent. Inaccuracies in Internet reporting aside, if you have concerns about their use, select something else for your mulch of choice. There are many others that would work equally as well, but to encourage the dissemination of inaccurate information is irresponsible and unnecessarily fear-inducing.

Always verify rumors and supposed warnings before passing them on.

Here's info from Snope's Urban Legends
http://www.snopes.com/critters/crusader/cocoa.htm

Here is a link that might be useful: Snope's on cocoa mulch

Here's an entire page of links to sites with info re hoaxes.

http://hoaxbusters.ciac.org/HBOtherHoaxPages.html

Here is a link that might be useful: links to pages w/info re hoaxes

The only thing I've heard negative about cocoa hull mulch is that it can form a mold that makes a crust on the surface. Not sure how big a problem that can be. I am proud of my fellow Master Gardeners who posted here and offered a different viewpoint.

To clarify, as it seems that the above responses, for the most part, are defining the cocoa mulch problem as a hoax or myth: go to the Snopes hoaxbuster site (which I have used many a time and find invaluable)and you will find that the original poster was correct in assuming that cocoa mulch is not a great choice if you have dogs. It may be unlikely that ill effects will occur, but it has happened. ASPCA does not recommend it; check out their report, linked at the bottom of the Snopes site.

Ginger
MG '99

OK, let's clarify a bit. Chocolate products that contain high levels of theobromine can be toxic to dogs and cats. This is neither a myth or a hoax. However, not all processed and commercially bagged cocoa hulls sold as mulch contain high levels of theobromine - many have been treated (primarily through extensive drying processes) to the point that theobromine levels are minimal.

The urban legend part of the story is that there is an immediate assumption that once cocoa hull mulch is applied, dogs and cats will be attracted to it from miles around and feed on it to the point of death. It is not necessarily widely available in all parts of the country and here where it has been sold for years, there have been very few reports of any accidental poisonings, let alone deaths, of family pets - much like previous reports of the deadly nature of Christmas poinsettas to children and family pets (truly a myth), it is a case of a few instances that get reported and blown out of proportion.

As to the issue of radically altering soil pH, there is no literature OR scientific documention to support it and logic would dictate it has minimal effect.

No one here is urging anyone to go out and purchase cocoa bean hulls to be used as a mulch. It does have value in that regard for a number of reasons, but its use is purely a personal choice. I don't use it myself because I prefer to mulch with compost and I don't care for the texture or the appearance through our wet winters. Also, I find the scent of chocolate cloying, even for the short period of time this stuff does emit such an aroma.

But the uniform labeling of "deadly" to this product without an understanding of the circumstances and all the variables involved is a bit of a stretch and unnecessarily alarmist.

GardenGal: Well said. Are you married? (just kidding)

Eddie: thank you and no. But not looking either :-)) Been there, done that.

I don't want to marry you either, Eddie.

***********************************

Our friend from the Pacific Northwest has stated it well. However, I also welcome the comments from Ginger, who as usual, is able to make additions to fully round out a discussion -- and there is nothing wrong with that.

Along that same vein, allow me to expand this whole discussion into an area that gets a little dicey. Some people do not like pets. I know, I know ... it is a hard thing for some pet owners to accept but it is a hard reality of the broad spectrum of the public that MGs have to deal with.

Particularly since there is a sizable number of irresponsible pet owners (it is the owner's fault - not the pet's fault) this is a topic that rankles more than a few gardeners. Although I am not condoning it: I know of gardeners who hope the neighbor's pet(s) will get into something poisonous. I have to say that over the years I have had more damage done to my gardens by other people's pets than by any other factor -- although squirrels rank right up there.

I grew up on the farm taking care of animals. I love animals but I hate the damage caused by uncontrolled animals. Well-trained animals are an absolute delight -- if only we could train some of the owners that well!

The analogy that I like to use is between smokers and pet owners. Personally, I think everyone should have the right to participate in either or both activities if they so choose. However, I donÂt think either has the right to impose their choice or the consequences of their choice on everyone else. I have answered almost as many Hort Clinic calls about neighboring pet complaints as I have about deer. The original poster seems to assume that everyone loves pets as much as she does. Over the years, one thing that I have learned as an MG is that you canÂt assume anything. There are a fair number of gardeners out there who donÂt like your pet and sincerely wish that they could avoid having to suffer the consequences of your delight.

IronBelly

Obnoxious people have obnoxious pets.