Dual-Batch Compost Tumbler from Gardener’s Supply: Product Review

We are avowed, long-time compost enthusiasts.  I so prettied up our compost area located strategically across from our “farm-ette” that I had designed borders and fabric “tops” and christened them “Compost Cabanas.”  We did a video there for a Hearst “Country Living” on-line tutorial.  You get the picture.  But we lost our two compost areas prior to a home renovation and I was in “mourning” while trying to figure out how to replace them.

So when I was presented with the opportunity to review the Gardener’s Supply Dual-Batch Tumbling composter, I was thrilled at the idea of putting this composter through its paces.

And the good karma continued.  The very day the “Compost Cabanas” came down for good, the doorbell rang and there was the Gardener’s Supply Dual-Batch Compost Tumbler box on the front porch.  It was kismet.


The Dual-Batch Compost Tumbler is made from recycled black polypropylene with steel legs. It’s lightweight but sturdy and takes up much less space than two traditional compost bins would – here are the overall dimensions: 28-1/2″ W x 25″ D x 37-1/4″ H. That means each of the two bins is about a foot wide and two feet deep, which isn’t very large.

Each of the two bins turns independently of the other by grabbing the slots in the outside of the bin and spinning it. They each have a sliding cover (you slide it away from the center of the bin to add or remove material from inside) and each holds about 3 cubic feet (22 dry gallons).

Simple Assembly But Incomplete Instructions

DuaL-Batch Compost-Tumbler the box

DuaL-Batch Compost-Tumbler still in the box

I immediately opened the tall box in the garage, laid out the components, and read the directions a few times. Note that you will need a bit of space to set the composter up: approximately six feet by six feet.

It was easy to assemble.  Too easy.  Turns out (no pun intended) that it wasn’t exactly clear that the two barrels of this duo have to be put together so both turn in the same direction.  The instructions don’t directly tell you to use the plastic tubes as axles for the two bins. Don’t throw them away! Just snap them into place inside the bins.

The assembly instructions for the legs can also be confusing. Make sure you’re assembling the composter on a level surface and that the parts fit cleanly together.

If you do put the composter together incorrectly, it can be readily fixed. But take your time and go carefully so you don’t make the same mistakes I did. 

All the bolts, screws, sturdy steel frames and poles, and plastic bins – with covers – are included.  Most of the assembly was done with just a “hand/fingers” and the rest with a wrench and screwdriver.  The manufacturer did a great job of keeping the set-up simple and easy to understand, as well as keeping the number of parts to a can-do minimum, but the instructions (particularly for the bin assembly and how to put the legs together) aren’t clear.

It took no more than 20-30 minutes to have this dual-batch composter up and tumbling.

Be careful putting the Dual-Batch Compost Tumbler frame together to ensure that all the parts fit properly

DuaL-Batch Compost-Tumbler Frame

DuaL-Batch Compost-Tumbler during assembly

DuaL-Batch Compost-Tumbler during assembly

A Word About Composting

Compost is the “black gold” product that comes from the biological decomposition of organic material. At its basic level, composting requires food, water and oxygen in the right amounts and ratios. It’s not difficult to make compost but if any one of the three components is missing, you won’t end up with finished compost.

>> For more details, see our Resources and Tips for Making Compost

I added some shredded newspaper, some weeds/greens and the contents of our compost pail that we keep under the sink in the kitchen that is a mixture of vegetable scraps, eggshells and no-meat leftovers, in addition to the “Brown” or dried material, including autumn dried leaves.  I also scooted to the local bait store and got more than a few containers of red wiggler worms for good measure to further aid in the microbial decomposition.

The Dual-Batch Compost Tumbler was placed on the southwest side of the house to take advantage of the microclimate of heat and sun there, especially for the winter.  And like any good composting regime, the compost area was located so that it was readily accessible from the kitchen.

How It Works

DuaL-Batch Compost-Tumbler

DuaL-Batch Compost-Tumbler Assembled

The beauty of the Dual-Batch Compost Tumbler is that compost is (theoretically) being made in one bin while the newly created decomposed composted organic matter from the other bin can be used in the garden.  One “cooks” while you’re making more compost in the other bin.

Each bin holds approximately three cubic feet.  While that may sound like an impressive load capacity, it fills very quickly – if you have a larger garden, it may be too small for you.

The bins are labeled “Start” and “Finish” on the sliding doors so you know where to add the scraps or yard material.  The doors aren’t very large, meaning that it can be difficult to remove the finished compost or add larger quantities of raw material (then again, this composter is on the smaller side in general, so that’s to be expected). And if you get debris in the slots where the doors slide, it can be hard to open or close them.

The tumbling or turning action aerates the material and it’s fun to do. But if you don’t turn the bin regularly, the material inside tends to “clump”, making it harder to turn. You may have to give it a bit of a wiggle to get it going.

It’s Slow Going in the Dual-Batch Tumbling Composter …

Once everything was put together and the bins were filled, the Dual-Batch Compost Tumbler seemed like a good investment. The only thing is, the organic matter I put in the composter never broke down.  It never decomposed.  I filled. I turned. I tumbled. And nada.  Nothing.  Zilch.

It seems that the holes in the bins don’t allow for rainwater or even melting snow to enter the bins reliably and frequently.  And water, as noted above, is a key element in producing compost.

I received the Gardener’s Supply composter in the late autumn and put it through its paces in every season.  The compost yield never improved.  Despite a rainy spring, it’s still as dry as a bone inside the composter.  I understand that the maker recommends watering the compost at the start, however I have to believe that most homeowners will not continue to water unless it’s explicitly noted in the directions or guidelines (and even then it’s questionable whether they’ll continue to add water).  I’d like to see Gardener’s Supply Company modify the instructions to tell people that water should be regularly added to the material in the “cooking” bin to keep it moist.


2_shovels The Dual-Batch Compost Tumbler is good-looking and despite falling over twice due to winds (you may want to anchor the legs to the ground), it’s quite sturdy and easy to manage. It’s odor-free (if you add the right materials) and easier to tumble than using a shovel or fork.

However, while this is a terrific composter concept, the Dual-Batch Compost Tumbler just doesn’t produce much compost and it’s probably too small for many gardeners. If you water it regularly, you may have better luck in making finished compost but based on my tests I give it a 2-shovel rating.

Where to Buy

The Dual-Batch Compost Tumbler is a Gardener’s Supply exclusive. It retails for $169 (plus shipping) although it’s currently on sale for $145. You can buy it directly from Gardener’s Supply, as well as on Amazon (where shipping is only $4.99).

Now over to you – Have you tried a tumbling composter before? How did it work? Let us know in the comments below!

And if you liked this review, [OptinLink id=1] please sign up for our weekly newsletter  [/OptinLink]with reviews and helpful articles.

Other Composter Reviews

Compost SakCompost Sak
Eco Stack ComposterEco Stack Composter
Green Cycler from EcotonixGreen Cycler from Ecotonix
Two-Batch Compost TumblerTwo-Batch Compost Tumbler


Disclaimer – GPReview would like to thank Gardener’s Supply for giving us a free Dual-Batch Compost Tumbler to review. There was no expectation that it would be a positive review and we received no compensation for writing it. All opinions expressed here are those of the author based on personal experience using the product.

Please note that the Amazon links (and only the Amazon links) above are affiliate links. Should you choose to purchase products through these links, GPReview will make a small commission (at no extra cost to you) that helps to support this website and our gardening product reviews. Thank you!