Introducing
My Homemade
Automatic Compost Sifter

Dateline: 20 June 2007


"It is not absolutely necessary to sift finished compost, but there is nothing so pleasing to the sensibilities of an organic gardener as a soft, homogenous mix of well-rotted vegetation. Sometimes referred to as humus, it is the glorious crowning achievement of all who compost."

That quotation is from my book, The Complete Guide to Making Great Garlic Powder, which was published back in 2003. With sifted compost in mind, I further wrote:

"I have sifted compost manually by shaking a screen-bottomed box over my wheelbarrow. In fact, I’ve probably sifted many tons of compost this way. I can tell you it’s a healthful exercise, particularly for the arms, shoulders and chest muscles. But if your garden gets very big, and your compost piles get to be the size of Volkswagen Beetles, and you need to get the job done fast, you’re going to need some help. Don’t even think about trying to convince your wife and kids that they will benefit from the exercise. It doesn’t work.

The Herculean task of hand-sifting massive quantities of compost inspired me to develop my own mechanical (motorized!) compost-screening machine. It is a continuous-feed barrel design. You shovel the compost in one end, sifted matter falls out the bottom, and all the unsiftables (rocks, sticks, missing spoons from the kitchen, and whatnot) exit the other end. This device is easy to build and fairly inexpensive. I plan to publish the plans one day soon."


Well, I never did publish those plans. But I may yet. The sifter sure does work exceptionally well. I just have to spend some time streamlining the design.

Since 2003 I have continued to use my cobbled-together prototype sifter. In this blog entry I’m going to provide you with some photos of the prototype and an explanation of how it works.


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The above photo was taken by me while standing atop this year’s compost pile (which will decompose down and be sifted next spring). You can clearly see the sifter and my son, Robert, shoveling sifted compost into my homemade Whizbang Garden Cart.

The sifter consists of a modified 55-gallon metal drum. The ends are cut out of the drum and sections of the sides have been removed. 1/4" hardware cloth has been fastened to the inside perimeter of the drum. The sifting drum rests on a stand. What you can’t see in the picture is that the drum is resting on four inline skate wheels. To make the drum spin, there is an electric motor underneath. A long V-belt runs from a pulley on the motor up over the top of the drum. The weight of the motor keeps tension on the belt. So when I turn the motor on, the barrel spins.

The motor spins at 1725 rpm, which is way too fast for the barrel to spin. I know this because I tried it. So the speed is reduced with a jackshaft and pulley arrangement. It now spins at 40rpm, which seems to be just right. If I ever refine this design into a Whizbang Compost Sifter, I willleave out the jackshaft and pulleys and just utilize a 40rpm gearmotor. It will make everything so much easier.

To use the sifter, it is turned on and shovels full of “raw” compost are tossed into one end of the barrel, as shown in this next picture:


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Note the compost pile in the background. It has rotted down very nicely and weeds are growing on the top. The weeds are no problem. The sifter separates them, as you can see in this next photo:


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The sifter barrel is slightly angled so the unsiftables migrate out the opposite end. Weeds, stones, sticks, pieces of plastic, paring knives, little army men; it’s amazing what finds its way into our compost pile, and out the end of the compost sifter.


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Sifted compost falls down under the screened drum onto an angled piece of plywood. I place a tarp on the ground and the compost flows down onto the tarp. It’s a joy to behold.


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The beautiful sifted compost is shoveled into my large-capacity, easy-to-wheel, incredibly useful, homemade Whizbang Garden Cart. From there I use the rich organic fertilizer to grow food for my family. I also use the compost when I plant my yearly crop of stiffneck garlic.

I hope you have been inspired by my homemade compost sifter. You now have the general idea and if you’re handy, you can go ahead and make your own nifty sifter. Otherwise, you’ll have to wait until I get the plans together.



19 comments:

Anonymous said...

is there a reason for not keeping your garden cart under the compost chute, to reduce one step of shoveling off the tarp?

Anonymous said...

It looks like a good one. Hope you get to those plans soon. Wish I had one of my own.
Thanks for sharing.

Anonymous said...

This seems like a very efficient system for sifting compost. Get yourself together and get it published!
:-D

Anonymous said...

Thanks! I will try to build my own version with my kids. (Mine will be kid-powered!) I have also been thinking of building something like this that can be powered by an animal, such as a goat. I'll share with you if I ever get that plan done LOL!!

tc said...

A great idea! I'm wondering if it will also work for sifting plain dirt (to get rocks and gravel out.) I'll have to add it to my future projects (after I finish my Whizbang Garden Cart!) Thanks again Herrick, for your practical posts!

eric : gardenfork.tv said...

Herrick, you remind me of my neighbor Mr Fruend, he's always inventing things, like his CowPots, made from manure.

I'm going to order your book and build a cart for my cooking and gardening video show, gardenfork.tv.

thx, eric.

Karen in WA said...

This is fantastic! I've wanted my husband to build one of these for years, after seeing a commercially built one that a friend of mine had. He was in the worm composting business and had one at least twice as large. It too was powered, but had a steeper angle than yours. The intent with the one I saw was to separate out worm castings and it worked extremely well! My african violets have bloomed non-stop after they received this wonderful screened compost!

Herrick Kimball said...

annonymous #1-
I would have had to raise the sifter barrel higher in order to get the sifted discharge chute high enough to feed into my garden cart. But if I raised the barrel higher, it would be too high to comfortably shovel compost into.

annonymous #2-
Thank you. I'm thinking about what my next book project will be. I have so many different ideas to write about. It does appear that this sifter is of interest to a lot of people.

annonymous #3-
Thanks for the encouraging words.

annonymous #4-
I would love to see your kid or goat powered sifter when you get it done!

tc-
Yes, it'll sift soil just fine. I used it once to sift rocks out of a couple of riased beds.

Eric-
Cow Pots! What a fine idea. Wish I could have thought of that. I've e-mailed you.

Karen-
I saw those worm sifters on the internet and they were part of my inspiration for making the sifter the way I did.

I should mention that my first compost sifter idea was completely different than the one I wrote about here, and it was pretty much a complete failure.

Sarah said...

I've just found your blog recently, and find it very enjoyable! I'm newly fascinated with homesteading and creating a simpler, more self-sufficient way of life. We live in the 'burbs but I hope to put some of your information and insight to good use in our own little backyard. Thank you and God Bless you and yours!
Best Wishes,
Sarah

TNfarmgirl said...

Herrick,
More pictures...or a book please. Especially of the placement for the skate wheels.

My boys were thrilled at the idea of NOT having to hand sift our compost/potting soil mixes. Right now we use a large screen placed in a wooden frame and they shake it back and forth - back breaking work!

Blessings,
Cheri

ButterflyGirl said...

Herrick,
I thought you might be able to dig out an opening beneath the sifter to put the cart in to catch the sifted compost. This would be a lot of work and would mean the compost station would always be located in the same place. That way you could still shovel in the compost at a reasonable level.

Thanks for sharing your experience and ideas! I'm seriously thinking of making something similar to yours!

Avrum said...

Hello, great idea, why not hook on a old bycycle to turn it ? Green power!

Anonymous said...

Hi, Herrick!

I would either add large ball bearings or large very round rocks inside the tumbler to help break/crush larger clumps. They should also prepare greens for further composting action.

Stan

Anonymous said...

Herrick, thanks for this blog and pics!
I found myself facing the same problem. Well, I don't have a metal drum sitting around and it seems like this project involves a lot of metal cutting, so here is what I'm going to try. I do have an old bike. I'm going to use its rims, remove spikes, connect them in parallel either with 3 or 4 galvanized steel rods or flat steel strip. Mesh goes on the inside just like in Herrick's design. Bike rims are pretty precise circles and should provide nice smooth operation. Rims are going to rest on 4 small rubber dolly/furniture wheels. Perhaps I would utilize its outside grove as a track for my dolly wheels. 1 front wheel and 1 rear are permanently attached to an axle (use round threaded rod or 1/2" elect. conduit) so that they don't spin freely. Axel it turned by v-grove belt speed reduction pulley (which is necessary in any case) propelled by a low RPM electric motor.

Where you can get parts:
8" Pulley - amazon.com;
Low RPM electric motor - kitchen appliance/mixer in local thrift shop;
Mesh - Orchid Supply
Steel rods - Home Depot
1/2 conduit- Home Depot
Zinc plated sheet metal - Home Depot

JoDel said...

Sounds great, I'm going to try to build one.

I also want to get into red worm farming for the compost and for chicken feed.

Temperature controlled worm bins cost $750 to many thousands! Have you (or anybody else) come up with a plan for DIY temp controlled red worm farm? Thanks!

46hillbilly said...

As a fella that has to do it the hard way. Cut the ends off of a steel drum leaving 6-8" of drum and use that to mount end to end supports. Then power the thing for rotation with a 1-4hp or 1/3 hp motor from a washer perhaps? Use a 1-1/2"--2" pulley and attach that to a driving wheel at the end of the drum. The driven wheel would have to be on an axle of it's own so it could be pivoted against the drum on a heavy spring perhaps?
Insert-able sizes of screens in this could vary the size of the output.

MelBugai said...

When are those plans coming out? We were sifting some flowerbeds and misc dirt/compost from around the yard and were tired of sifting by hand. So we sketched up something like this and then found your site. We were thinking about using a cordless drill. We also were thinking about making it easy to set up & break down so that we can store it easier.

I really look forward to seeing how you built yours! Please post the pans soon!

Anonymous said...

Is this plan available, perhaps in your new book? Would love to try it.

Herrick Kimball said...

Sorry but the plan is not available. Although the sifter works very well I am not satisfied that the drive mechanism is as good as it could be and need to do some redesigning..... someday. Check out YouTube for some sifter ideas. Last I checked, there were a few good sifter concepts there.