Beware the Chocolate Mulch

May 12th, 2007

chocolate mulch It sounds good on paper. Cocoa bean husks used as mulch, get use out of a waste product, smells nice as you walk by. I’ve seen this mentioned on websites and on TV shows. But I have never seen it in a store.

This Spring through I saw a bunch of bags at Meijer and decided to try one. It does smell like chocolate, unfortunately its almost useless as a mulch.

One week outside with a few days of rain and it turned into a clotted moldy mass with the consistency of a brownie. I’m not adverse to seeing various types of fungus showing up on mulch, its just doing it’s thing turning it into compost. This mold though, it was a sickly bluish white color, looked more and smelled more like bread mold or other mold you find on something lost in the back of your refridgerator. Plus, it only took a week to get like that. Usually it takes a full year for wood mulch to get clumpy like that. So I had to pick it all up and compost it, didn’t seem like a great thing to be growing basil in, plus I also noticed atleast one critter was getting into it.

So, be warned, cocoa bean husk mulch is a bad idea.

Posted in: Gardening, Troubleshooting »

35 Responses to “Beware the Chocolate Mulch”

Chris De La Rosa Says:
May 15th, 2007 at 5:02 am
we owned a small cocoa estate in the Caribbean before I moved to North America and if you think it’s nasty looking as mulch… you should see it after it’s harvested and put to dry into cocoa beans. It’s basically covered in that white fungus substance similar to what you mentioned.
20 minute Jan Says:
May 16th, 2007 at 7:00 pm
I’ve walked by public gardens where cocoa mulch was recently applied and found the scent really mouth-wateringly delicious.

Our favorite pre-packaged mulch, however, is cedar chips. They are mildly aromatic, highly durable and slow to decompose. The cedar mulch layer can be pulled back easier to plant. Cedar is also reputed to discourage pests and mildew. We’ve had enormous success with it.
Wicked Gardener Says:
May 17th, 2007 at 7:51 pm
This stuff sounded irresistible and I did some research on it this week. Most of the sites mention that it can be very toxic to pets, especially dogs. This is the first I heard about it being unattractive too. Sounds like a no-go. Thanks for the post
Laura Says:
May 26th, 2007 at 7:51 pm
Egads. I, too, succumbed to the lure of the cocoa bean mulch, mainly because I liked the color and wanted something that would break down in one year. I just put it in one of my beds. I will be on the lookout for the yucky mold now. I did read at the Nationals Cocoa Shell page that the mold could be washed away.
Adam Fletcher Says:
June 10th, 2007 at 7:24 am
I also heard that these were really toxic to some animals in the garden.

Thats why I have avoided them in the past

Adam Fletcher
Kari Hayes Says:
July 5th, 2007 at 10:23 am
I’ve only just now discovered your blog. Just wanted to say I, too, was thrilled to hear about all the different mulches out there that put “waste” to good use. I didn’t try the cocoa, but went with the pecan shells instead. They weren’t a disaster, but I won’t use them again. They’ve composted nicely, but WOW! Don’t ever forget you’ve used them and make the mistake of stepping into your flower bed bare-footed! I can’t tell you the new dance steps I created while trying to get off those shells! NOT a good feeling!:)
One more thing – I really enjoy your blog.
Erin Says:
July 8th, 2007 at 10:33 pm
I applied the cocoa bean mulch and noticed the mold, too. However, the mold does die out! It is harmless to the plants and it just runs its course. I have found it to be very beneficial to the soil and it looks great. Just be careful if you walk on it when it’s wet as it get very slippery when wet (hmmm, sounds like a good title for an album)!
Barb Says:
July 10th, 2007 at 9:20 am
I have been using cocoa bean mulch for a couple of years and really struggled at first with the odor as one of my gardens is right under my living room window.

Surviving that, now I’m concerned about the mold. I’m not allergic, but I suspect this could be an issue for some folks. Mostly, I’m beginning to wonder if the mold isn’t killing my impatiens. I noticed they weren’t growing very fast despite regular watering. Then I put a blood meal fertilizer around each plant. They’ve been dying left and right. So, is it the mulch or the blood meal? Either way, I’m taking out the cocoa bean mulch, my dead impatiens, and am starting all over again with new soil for next year. Bummer!
Gretchen Says:
July 25th, 2007 at 2:08 pm
We used cocoa bean mulch a couple of years ago and had loads of positive comments about the smell from visitors – but after smelling it for several weeks – I soon grew to hate the smell, myself. We never got the mold on it – but we did have a lot of trouble with it floating away after a good rain since it was so light; and at almost three times the cost of cedar mulch, we decided to go back to the boring old cedar.
Yetti Says:
August 6th, 2007 at 6:18 pm
I just applied the CBM about 3 weeks ago after seeing it in a friends garden. Everything was fine at first, then a couple of days ago, we had hot, humid weather with no rain for in sight, so I water a couple of times a day (I also have thirsty impatiens, but they are doing really well)and that’s when the white fuzzy mold started. In fact, all my plants are doing well, but the mold is unsightly, especially considering how pleased I was after the initial application. Has anyone heard of/tried some sort of anti-fungal formula applied to the CBM??? I read about it on another site. If that works, I would try…I love CBM compared to the bark mulches. I think it has a more natural, subtle look to it. BTW, since it’s forming mold, does that mean it’s retaining moisture (which is my main purpose)??.
Patrick Bowling Says:
September 27th, 2007 at 1:51 pm
It’s interesting that you mention that the mold is turning it into compost. If you get back this far in your blogs, I was curious if these would be considered browns or greens when added directly to a compost heap. With weekly lawn trimmings, there seems to always be plenty of nitrogen, so I was hoping that these may be a good source of carbon. I usually run out of back stocked leave around june.
Administrator Says:
September 27th, 2007 at 7:25 pm
Brown, but the reason I didn’t like the mold, in addition to it being unsightly, was that it compacted & compressed the mulch so that water wasn’t getting in and the plants were having a hard time breaking through it.
Lynn Says:
December 19th, 2007 at 7:17 pm
I love my CBM, I put it down under my gardenias and not a weed in sight no snail. Yes at the beginning you will have mold but that goes away along with the smell. That was last year and ready to do it again this year.
Brett Says:
December 26th, 2007 at 5:47 pm
My wife loves chocolate, so I put the CBM in my front yard. The mold came after a few weeks of DRY california weather. I started to throw out the CBM but then heard it was harmless and beneficial. I’m not a fan of the mold but think I’ll let it ride in the rest of the garden. Thanks for the info everyone.
David B Says:
June 11th, 2008 at 11:30 am
I’ve been using cocoa shell mulch for around 6 years. My soil is pitch black and loaded with worms. My only complaint is weeds still get a good anchorage. I’ve heard cedar mulch is a better weed preventer but is slow in breaking down and turns gray. I’m curious would mixing the two be a good idea or not?
Karen Says:
June 1st, 2009 at 5:40 am
I tried CBM for the first time this year. In the first days I enjoyed the light aroma of chocolate and the attractive look of the mulch. Then the mold started and the chocolate smell was gone. Mold was light during the first weeks but by the fourth or fifth week the mold became thick and you couldn’t avoid the stench. It started as a thin layer of slimy mold that appeared to come and go. Then expanded to cover the entire area. Old mold dried white and thick. Eventually we had to keep the house windows closed because of the awful stench and how it made us feel. It caused irritation and pain in my nostrils that’s been continuous for more than a week with little relief during the full days I’m at work. My spouse has been complaining about throat irritation for several weeks. Our indoor pets started sneezing several days ago. Friends start coughing and grabbing their throats as they approach the door. I spent this weekend removing the mulch. Never again.
Jeff Says:
June 10th, 2009 at 10:04 am
You must have something else causing that much mold. I have the cocoa shell mulch and I also have some mold. It goes away when the shells dry out or is exposed to sunlight. It does not smell, at least the mold in my garcen does not. You may want to seek help from your local garden center to identify the mold.
Lesley Young Says:
January 14th, 2010 at 2:33 am
I have been using the cocoa bean husk as mulch for about a year now and found it to be a fanatastic soil conditioner. Weeding is much easier to do in a spot where I have put a thick layer of the mulch down after a few months, the soil is very friable as a consequence.

It does get mold, but it’s not slimey and it’s just evidence to me that it’s breaking down.
The local garden centre gets it in by the truckload from the chocolate factory and it goes out the door immediately. There are waiting lists for it when it comes in.

I live in New Zealand and the patrons of the garden centre here are avid gardeners due to the temperate climate and good growing conditions we have here. I’m sure they are only buying it because of the good results from it.
Jeffrey Says:
April 17th, 2010 at 12:19 pm
I’ve used CBM for years and like someone else has mentioned, I now have amazing dirt. Using large chips of some other kind of mulch will take a very long time to break down by comparison. Yeah, it does get mold, usually only for a week or two, but it goes away. It also darkens with age versus the colour dulling with other mulches, which I think is another definite plus of CBM. I have found that it isn’t great about keeping the weeds out but since it makes the soil condition so fantastic, any weed is trivially removed without any garden tools. All that said, I have a lot that neighbours a park and I don’t use it along that side of the lot – I don’t really want to take a chance that someone’s dog is going to eat it and then come after me with a lawsuit..
Katie Says:
July 3rd, 2010 at 12:10 pm
I just planted some hostas this year and recently put the CBM around them but not close to the stems. Before putting the CBM down, the hostas were getting big and blooming, but after putting the CBM in that area the leaves started to wilt and they are really saggy. Has anyone had this problem before? I am trying to figure out if it’s from the CBM. I love it, the smell and the look is wonderful. I haven’t had any mold, it’s beautiful mulch!
Anna Says:
June 7th, 2012 at 8:05 pm
Do you think the cocoa bean mold would be bad for basil? I have the mulch and some mold and all the other plants in my garden seem to be doing fine but the basil is yellowing and may have tiny black stuff showing under some of the leaves. It may be some other basil fungus or bacteria from the soil but now I don’t know if that’s what it is and if I can grow basil in the soil ever again. Maybe in a pot instead?
Maui Skye Says:
June 12th, 2012 at 9:47 am
My boss (orchid grower in Oregon) bought a bag of it to mulch around the office/house a few years ago. A bear liked the smell and picked up the bag and took off through the woods with it. I followed the trail of cocoa bean mulch to pick up the empty bag. The bears claws (teeth) shredded the plastic bag as he was carrying it away!It smelled great, but didn’t try it again.
diane peterson Says:
June 19th, 2012 at 7:19 pm
I just put down coca mulch and a few days later had big orange patches on the top. Most were under plants but some were in sun. Not a uniform problem, just in a few patches. When I put water on them I got a cloud of orange erupting so I assume it is a fungus. Doesn’t seem to be harming anything. Should I be concerned or just assume this is a natural part of cocoa bean mulch?
Ian Brown Says:
June 30th, 2012 at 12:16 pm
We have used cocoa husk mulch with great success. We had some surface mould but it only lasted a few days. Best mulch we’ve ever used and much more attractive than cedar. It is also resistant to termites.
linda Says:
July 1st, 2012 at 6:21 am
I put the cocoa mulch down this year and yes the mold did start growing. We did notice alot of flying tiny bugs all over the windows just above the mulch and in the mulch itself. The bugs in the mulch are jumping larvas at least that what they look like. I will never use again
William"The"Wonder Says:
October 14th, 2012 at 9:13 am
Cocoa Bean Husks and most coco coir, although different, both contain Trichoderma forms of mycorrhizae, a “benefical fungi”. Myco typically contains Fungi’s and Bacteria’s that are both benefical to all plants including fruits/veggies and other amazing herbs that typically get eaten. Regardless the benefical or not, warm water will repel the mold for awhile if you completly saturate the medium.
Never liked chocolate anyway Says:
July 2nd, 2014 at 12:08 pm
Ugh, this stuff is BRUTAL!!
Of course it looks beautiful for about week…then orange patches of mold appear(resembling the sawdust stuff janitors used to sprinkle on vomit back in grade school) BLAHK!! For extra special fun, you may also notice hundreds of flies hatching just under the surface. I’d rather put steaming piles of ???????? all over my yard!!
bob Says:
July 17th, 2015 at 12:05 pm
Slipped on the wet cocoa mulch the other day and almost broke my neck. We have had a lot of rain and heat. The mold has attracted thousands of flying bugs. I think it will be great for amending the soil. It breaks down fast. It gets slimy too. I am mixing it with my rototiller.
Teresa Says:
June 19th, 2016 at 1:01 pm
Come on people. It tells you right on the bag about the harmless white mold. It’s not the deadly black mold. Simple fix, been using it for years. Mold appears in high humidity, usually disappears in a few days if your not overwatering and can be sprayed lightly with 50-70 parts vinegar to 50-30 parts water. Don’t spray in wind and don’t spray directly on your plants. I’ve only ever had to spray one time per season. Love the stuff!
Russell Says:
June 29th, 2016 at 9:58 am
The mold goes away and so does the smell. The best thing is that ghe color does not. If you like dark mulch, CBM just keeps getting darker. You lnly need about an inch of it and it lockstogether forming a mat that keep moisture in an keeps weeds from breaking through. I love the stuff!! Been using it for 4 yrs now.
Janie Says:
July 23rd, 2016 at 7:16 am
I have used CBM for years with great success. I bet geographical area has a lot to do with how cocoa bean hulls perform. Today, for the first time ever, we woke up to a white foamy mold, between 1-2 inches thick all over the garden. Looked like snow in July! Took lots of great pictures as the heat index here in Chicago is expected to be 110 degrees today. I usually just use a rake to stir up the mulch when it gets any harmless mold on top. The benefits far outweigh the challenges of CBM for me:)
Jack Says:
June 13th, 2017 at 7:19 am
Cocoa bean mulch was infested with ‘cheese skippers’ a little worm that jumps when watering the garden. Report to better business bureau BBB as soon as possible. I bought mine at menards. Very nasty and can cause severe illness!!
Kerri Says:
July 1st, 2017 at 11:47 am
I use cocoa mulch in my raised vegetable beds and it is perfect. Looks and smells great, and in full sun it is not moldy. It greatly improved my heavy clay soil, is cheap, and one bag covers more are than bark mulch. This year I also put it under some cedars and hostas at the back of the yard where it is shady and it is very moldy. The plants are doing well, but it looks awful, so after this, I will stick with wood mulch in shady areas, but keep using my cocoa mulch in sunny areas.
Amanda Parish Says:
October 8th, 2017 at 6:41 pm
CBH is by far my most favourite garden mulch. Yes, I noticed the mould but two years later we are still using it regularly and the results in my opinion are outstanding. In particular my herbs have boomed like nothing I’ve ever seen. Single rocket and coriander plants became small trees and almost took over the garden. Herbs like true Greek oreganum, sweet margoram and thyme have flourished with pungent flavors. In fact it would be difficult to argue that there was a single plant that didn’t flourish from heavy use of cacao husk. I basically turned straight sand into soil gold with some household compost and lashing of husk.
Lonnie Weigele Says:
November 16th, 2017 at 7:56 am
I have been using cocoa shell mulch for years and love it. Yes, when it is humid for a few days it gets moldy, but as soon as the weather dries, the mold disappears. The cocoa smell goes away after a bit, but each new spring, I put down a layer of topsoil over the cocoa shell mulch and then put a new layer of the cocoa shell mulch. As it ages, the dirt becomes so black and rich, it is awesome. I have no complaints with it in the flower, shrub gardens. I will continue to use.