Why move compost to another bin? 3-bin compost system

[Vincent]

When using a 3-bin compost system, why should you move compost that is ready at a stage to the next bin? Are there benefits? It just seems extra work to me.

I was reading this:

• Step #1: Add organic wastes to bin A until it’s full.
• Step #2: Turn bin A’s contents into bin B.
• Step #3: Refill bin A while bin B’s contents mature.
• Step #4: When bin A is full again, turn bin B into bin C. Then turn bin A into bin B.
• Step #5: Refill bin A. (By the time bin A is full again, the compost in bin C should have matured, and bin B should be halfway there.)
• Step #6: Empty bin C by using the compost.
• Step #7: Continue the cycle by moving bin B to bin C and then bin A to bin B.

A less intensive workflow could be to turn bin A when full with organic wastes one last time and leave it in the same bin. Then start filling bin 2 with organic wastes. etc.

 

[Steve @ Celtic Farm]

Short answer: A 3-bin system allows for an ongoing cycle, especially if you produce regular organic waste. Long answer:

Different Decomposition Stages Each bin in the system represents a unique decomposition stage. By sequentially moving compost, each batch matures without disturbance from new additions.

Aeration Benefits Turning compost introduces necessary air, speeding up aerobic decomposition and preventing smelly anaerobic conditions.

Temperature Control Regularly moving compost helps it maintain heat, breaking down materials and killing pathogens and weeds, ensuring a sanitary product.

Consistent Results The 3-bin method ensures the final compost in bin C is fully matured and consistent. By the time compost reaches this final bin, it's gone through thorough decomposition.

Space Efficiency This system is space-smart. While one bin fills, another matures, ensuring there's always room for both fresh waste and maturing compost.

Easy Monitoring Separate bins mean easier maintenance and monitoring. If one batch has an issue, it doesn't compromise the entire operation.

The alternative you mentioned, turning and maturing compost within a single bin, can work. But it might not handle continuous waste input as efficiently as the 3-bin system, which ensures faster, regular compost production.

 

[redback]

I have a three-bin system and I have to turn the heaps twice to get full decomposition.
If you have a shredder (mulcher, mower, chipper or chafer) decomposition would be quicker and more complete than if the material is not chopped. However, the good mulchers are not cheap, and everything has to be stockpiled, chopped and then composted. Same amount of work either way.

 

[DirtMechanic]

I run thinwall pvc pipe (6 inch x 10 feet with .75 inch holes) under mine so I do not move it as much. There will be a crust of uncomposted material on top. I move it when I get some out. I use a pitchfork. 3 bins make for a good continous system and is a good way for larger piles where a front end loader can be used. @Steve @ Celtic Farm gave a very clear comprehensive list, one of the better I have seen. I have a tee shirt from a local nursery that says "compost happens" so in that vein of thought mainly I spray some water on it and give it privacy.

 

[Meadowlark]

... I spray some water on it and give it privacy.

Here's a tip that works in all compost systems: water only with captured rainwater. Chlorine in tap water defeats the purpose and well water has almost zero oxygen content.

Rainwater provides far superior results than achieved with tap water and/or well water. Set up containers to capture the rainwater so you can apply it whenever needed.

My three-bin system for super compost is pictured below. Containers (about 25 gallons each) are layered with cow manure and then green high nitrogen fixing shredded plants alternating to the top. I use Sunn Hemp for my green layers but alfalfa, beans, peas, clovers, would also work.

The lids provide protection against loss of N2 and ensure that nothing but pure natural rainwater is used in the process. They also eliminate smells. These mixtures do not have to be turned...just make them up and let 'em set. No labor, no smells, no animal damage, no flies. They are also very portable.

I have "soil tested" this compost with the resulting lab recommendation: "No N P K required." The test was on nothing but compost from the above system. I call this "super compost" and it yields results like no other, especially commercial products.

I challenge anyone to match the composition results shown below with just kitchen/yard wastes.

Raw Soil Data​

A closer look at your soil, results are provided in parts per million (ppm).

Nutrient	Your Results	Optimal Range	Rating
pH	6.37	5.8-7.0	Optimal
Total Nitrogen (N)	38.91	32.0-60.0	Optimal
Nitrate (NO3-N)	30.14	-	-
Ammonium (NH4-N)	8.77	-	-
Phosphorus (P)	31.59	8.0-20.0	High
Potassium (K)	114.79	38.0-80.0	High
Sulfur (S)	9.92	7.0-22.0	Optimal
Calcium (Ca)	83.01	80.0-320.0	Optimal
Magnesium (Mg)	33.68	27.0-70.0	Optimal
Sodium (Na)	13.81	0.5-30.0	Optimal
Iron (Fe)	1.27	3.0-10.0	Low
Manganese (Mn)	4.7	4.0-10.0	Optimal
Zinc (Zn)	0.17	0.1-0.25	Optimal
Copper (Cu)	0.03	0.06-0.3	Low
Boron (B)	0.01	0.2-0.6	Low