I've used cocoa bean mulch for years, but only in the beds at the front of the house. The cost for the mulch was too much for use throughout the garden. That seems to have changed. What used to run $8 a bag can now be found at large box stores for ~$5 a bag and since cocoa bean mulch goes so far, this is a bargain.
You should not use cocoa bean mulch if you have a dog that will have access to it. It's toxic to dogs and my vet tells me he sees a couple poisoned pets a year because of it. Some don't make it. However, if you have areas where you can safely use it, it is a fabulous mulch.
The hulls of cocoa beans are all the same size. That means the mulch lends itself to a very neat appearance. Once down and wet, it quickly binds itself together as the hulls interlock. This means it is a fairly effective weed barrier, for weeds needing light to germinate. Water penetrates it but light does not. Cocoa bean mulch also seems to retain moisture better than traditional mulch, probably because less soil is exposed to air. It is also more fire resistant than wood, leaf and pine straw mulches.
Cocoa bean mulch lasts longer than other organic mulches. It also doesn't fade in the sun. It gets darker, turning to a dark brown. It doesn't wash away in rainstorms and it's decomposition is slow enough that you can get away with putting it down every other year. Ants don't seem to be drawn to it, like they are to wood mulch. Slugs, at least in my garden, seem to hate it. Cocoa bean mulch (that is fresh) smells like a bakery when you put it down, however the smell doesn't hang around long, so don't buy it just for that. The smell lasts about three weeks if it's dry outside, less if it's rainy.
It's a very clean mulch. It's dusty when you first put it down but once rinsed with a hose, it's not messy at all. The cleanness of it, as well as it's decrease in price inspired me to try it in the greens area today.
I hate it when dirt splashes up on the lettuce leaves, but natural looking mulch choices that won't harbor slugs to prevent splashing, are few. Cocoa bean mulch, however is nearly perfect. It's small size lends itself to easily fit around already established plants. It's light weight means it was safe to spread among the carrot seedlings and other tiny seedlings.
Purchasing: I have a few tips for working with cocoa bean mulch. First, when you purchase it, the best stuff is stored sheltered from the rain. When left exposed outdoors but confined to bags, the bags can develop huge fungal balls within them. Select bags that smell richly of chocolate. Ignore those that smell musty. Take your bags from the middle of that pallet, they will be the driest. The bags should be very light. Two cubic feet should be able to be lifted without effort. If it feels heavy, it's been wet and pass it by.
Application: Since it is so effective at blocking light and tiny seedlings will have trouble breaking thru it once it's interlocked, wait to put it down until you have everything in that area sprouted. Also try to have everything planted. Digging in it, can spoil the look of it. You don't need to have the entire garden ready. You can use it to make interesting bed within a bed visuals by putting it down a bit at a time and keeping the edges neat.
Wear dark, old clothes to put it down. The cocoa bean mulch dust will stain a t-shirt just like a chocolate bar. Apply it in the garden on a day that isn't too windy. It's very light, and it's easier to get down on calm days. Don't worry, it won't blow away in the next wind. Once down and wet once, it holds together great. I live in a windy area and have had no trouble with it here, however if you are dealing with wind and a steep slope, or applying it over dry newspaper you might. It's that light. It's also a good idea to start putting it down early enough in that day that the plants in the bed will have time to dry out before night-time. You will be watering the mulch.
I don't let my kids help with putting this mulch down. It's an agricultural product that has a fair amount of fine dust in the bag and it mostly is imported. I think it's prudent to wear gloves to put it down, don't toss down open bags to make dust clouds in front of your nose and if broadcast spreading, stay upwind of it. It's not at all horribly dusty, but there is enough of it that you should pay attention to what you are doing.
I apply the mulch close to plant stems, but not on top of them. The hulls have sharp enough edges that they could cut thru a fragile stem. The package calls for an application depth of 2 inches. I think that is much more than is needed. Once inch gives very nice coverage. 1.5 bags of two cubic feet mulch did the entire area in these pictures. As I said, it goes a long way!
Once you have all the mulch down, wet it immediately. Wetting it washes the dust down and immediately shows you any areas you missed or applied it too thin. If you see dirt, add mulch to those areas. Once patched, wet it again, to wash the dust off the plants and start to bind it together. That's it! Easy peasy and neat and tidy.
I've gotten most of the greens area covered now. Eventually, I'll mulch this whole bed with it but first there is some planting to be done along the hedge. The mulch is working perfectly with the lettuce. They can now be watered without any dirt at all getting on their leaves.
My other favorite places to use this mulch is in window boxes and in planters that the dog doesn't have access too. Not only does it look nice, but they planters and boxes lose moisture at a slower pace and dirt holes don't develop when watering in those areas. If you garden in dog free areas, give it a try!