SITUATION STATEMENT: Composting on site could be an advantage for municipalities that collect yard waste. If a large percent of homeowners in a municipality composted their own yard waste, less time and money would be needed for pickup and composting. Some municipalities have concluded that it is cheaper to cost share a compost bin with homeowners than it is to pick up yard waste. At present, many municipalities in Brown County collect yard waste. It would be important for them to know which bins would be the best choices should they decide to promote a bin program. OBJECTIVES: To test 10 (or more) commercially manufactured compost bins and compare: (1) rate of composting; (2) ease of handling; (3) cost; (4) size.This is the third part of a three-year study. Please refer to last year's study for a summary of what occurred in 1995.

PROCEDURE & RESULTS: On June 12, 1996, Master Gardeners and I spent several hours mixing 2/3 "brown" material (mostly six-month-old leaves) with 1/3 "green" material (mostly grass clippings from June 1996) in a concrete bunker that had at one time been used for salt storage. This activity took place behind the Agriculture & Extension Service Center, 1150 Bellevue St., Green Bay, Wisconsin.

After that, on the same day, 11 commercial compost bins and one homemade bin were set up and filled with the mixed material. The amount of material put into each bin "filled" each bin. Actually, the material was measured by pail into each bin until the smaller ones were filled. The larger ones were added to until we used all the mixed material. Temperatures were taken in the center (hottest) of each bin. Temperatures were recorded for all bins for 15 days.

Compost bins were maintained weekly by Master Gardener Harvey Plansky and others. Bins that needed tumbling were tumbled and water was added where needed.

EVALUATION: Temperature data was used to determine high thermophilic bacterial activity. According to composting experts in Wisconsin, "A pile needs to be in the 130 to 160 degrees F. range for optimum decomposition1." The data shows a wide variation from bin to bin. The bins that sustained higher temperatures longer were judged to be superior in the rate and extent of decomposition of the compost material during the time frame studied. However, Richard Albert, bacteriologist, says, "Higher temperatures do not always indicate faster composting." Composting by bacteria, fungi, etc. does continue at lower temperatures. All the bins had a good amount of composted material. Compost maturity may not occur until much later than the study's time frame. We did not test for compost maturity.

Bins 3, 5, 7 and 11 had a mean temperature of 113.0 F. Bins 1, 2, 4, 6, 8, 9, 10 and 12 had a mean temperature of 95.9 F. This is a statistically significant difference with a 95% confidence level (see Tables One and Two). If you equate the mean temperatures with advanced decomposition, then bins 3, 5, 7 and 11 initially decomposed more quickly than the rest. This also correlates with nutrients available (see Plot #1) factor analysis comparing nutrient availability with temperature.

FASTEST DECOMPOSITION:

Bin #3 = 40 cu. ft. (not covered)
Bin #5 = 18 cu. ft. (not covered)
Bin #7 = 22 cu. ft. (not covered)
Bin #11 = 14.5 cu. ft. (not covered)

SLOWEST DECOMPOSITION:

Bin #1 = 18 cu. ft. (covered) 
Bin #2 = 12 cu. ft. (covered) 
Bin #4 = 6 cu. ft. (covered) 
Bin #6 = 10.5 cu. ft. (covered) 
Bin #8 = 14.8 cu. ft. (covered) 
Bin #9 = 12.5 cu. ft. (covered) 
Bin #10 = 9 cu. ft. (covered) 
Bin #12 = 23 cu. ft. (covered) 

Bins 3, 5, 7 and 11 were uncovered bins, therefore receiving more natural water and thus keeping the compost going longer (we watered the covered bins but only as they dried out). The largest bins not covered did the best (as decomposition relates to sustaining temperatures). If we had uncovered all the bins we would have had a fair comparison. We didn't do that because we wanted to test the bins as set up by the manufacturers.

It is our hypothesis that most people will not work too hard at composting. Therefore, the open bin (natural watering) with the biggest volume (that doesn't dry out) will do the best. That includes bins 3, 5, 7 and 11. We liked bin #3 the best because of the expandable volume going up to 40 cu. ft. Can we say statistically that some bins worked better than others? Yes, we can, but only for the reasons mentioned above. For the average composter and most municipalities I would recommend an open-topped, large-volume bin. Bin costs (of the open tops) were also significantly lower. Bins that were the most trouble to use were bin #4 (small volume, dried out quickly) and bin #12 (too heavy to roll).

All the bins were easy to assemble. The open-top bins were less work (extra watering not needed). Then you have less control. (If in a humid climate you may have too much rain on them!) Activators and turning were not used in 1996 because they did not change decomposition significantly the first year.

IMPLICATIONS: Homeowners can easily compost yard waste in their own yard. The bins tested looked good, did not occupy much space and were not subject to rodent infestation. Cost and ease of handling would be major factors in choosing a bin. We did not test all bins available on the market, but it is likely that many other bins would perform as well as the ones tested. Homemade bins should also compare favorably with commercial bins, if they were large enough.

ACKNOWLEDGEMENTS: Thanks to all the distributors and manufacturers of the bins we tested. Backyard composting is a viable option to help homeowners recycle on site. Thanks to Master Gardeners Harvey Plansky, Lloyd Giese, and others for much of the physical work. Thanks to Richard Albert, bacteriologist, and John Peters, soil scientist, for reviewing this document.

1.Maureen Mecozzi, Waste Reduction and Recovery Program, DNR Bureau of Solid and Hazardous Waste Management, 1969.

Bin #	Name of Composter Name of Manufacturer	Available at	Approx. Cost1	Size	Ease2 Easiest=1 Hardest=10	Rating3 Superior=1 OK=2 Needs Imprvmnt=3
1	#3735 Rubbermaid Composter Rubbermaid, Inc., 1147 Akron Rd., Wooster, OH 44691	ACE & True Value Hardware	$89.00	18 cu. ft.	1	2
2	Four Panel Deluxe Composter North States Industries, Inc. 1200 Mendelssohn Ave., Minneapolis, MN 55427; (612) 541-9109	ACE Hardware	$49.00	12 cu. ft.	1	3
3	Covered Bridge Composting Bin Covered Bridge Organic Farms Coop P.O. Box 164, Jefferson, OH 44047 (216) 576-5515	Direct from factory	$40.00 delivered	23 & 40 cu. ft. (adjust- able)	1	1
4	Green Magic Tumbler Gardener's Supply Company 128 Intervale Rd., Burlington, VT 04501 (800) 876-5520; (802) 863-1700	Order from Gardener's Supply Co. Catalog	$119.95	6 cu. ft.	5	3
5	Presto Home & Garden Compost Bin Presto Products Co. 1831 W. Winnebago, Appleton WI 54913 (920) 738-1440	Direct from Presto Outlet in Appleton	$7.50	18 cu. ft.	1	1
6	The Earth Machine Norseman Plastics, 39 Westmore Dr., Rexdale, Ontario M9V 3Y6 Canada (800) 267-4391	Direct from factory	$49.00	10.5 cu. ft.	1	2
7	#5201 Handy Composter Wilmarc, Inc. 5266 E. 65th St., Indianapolis, IN 46220 (317) 849-9596	Direct from factory	$19.95 delivered	22 cu. ft. (adjust-able)	2	1
8	CP100 No-Turn Composter Gardener Equipment Co., PO Box 106, Juneau, WI 53039; (414) 386-4880	Mills Fleet Farm	$80.00	14.8 cu. ft.	3	2
9	Soilsaver Barclay Recycling, Inc., 75 Ingram Dr., Toronto, Ontario M6M 2M2 Canada (800) 668-8430	True Value Hardware	$60.00	12.5 cu. ft.	5	2
10	Green Keeper Compost Solarcone, Inc., P.O. Box 67 16438 Second St., Seward IL 61077-0067 (815) 247-8454	Direct from factory	$100.00	9 cu. ft.	4	2
11	Wooden Bin Composter	Homemade	$35.00	14.5 cu. ft.	1	1
12	Bio-Orb Composter Shape Plastics Corp., PO Box 538, Sharon, WI 53585 (414) 736-8888	Menards	$99.00	23 cu. ft.	10	3

1. Costs were retail costs in 1994. Changes for 1995 were not noted.

2. Ease includes set-up.

3. Overall rating includes rate of decomposition, length of high temperatures, favorable C/N ratio changes, & total N available.

Date	Bin Number & Temperature Inside Bins												Time	Air Temp	Comments
	1	2	3	4	5	6	7	8	9	10	11	12
6/12	84	82	84	93	84	81	80	84	92	83	83	84		82	Orig. temps. within 1/2 hour of filling. Bin 3 filled 1/2. Watered 3 qts. Filled 1/3 green, 2/3 brown. Started June 4 (1/4).
6/13	138	126	141	106	136	129	137	139	133	136	135	130	7:20 AM	70
6/14	145	141	153	107	156	152	154	156	151	153	153	143	7:30 AM	70
6/15	142	136	152	99	151	144	151	151	145	146	150	125	6:50 AM	56
6/16	132	118	151	89	148	142	152	141	134	140	144	108	7:05 AM	64
6/17	103	89	128	69	130	98	138	115	100	110	128	85	10:00 AM	62
6/18	88	80	125	68	104	84	120	94	90	94	104	67	9:00 AM	60	Rain for 2 days. High yest. 65. Rain 1.5" (3/4" overnight)
6/19	72	74	115	64	100	80	100	86	83	84	92	66	8:00 AM	59	High yest. 65 with rain. Today misty, no sun.
6/20	72	74	108	76	95	74	91	80	82	80	90	76	9:00 AM	75	High yest. 72, low of 65.
6/21	80	78	115	84	97	85	100	86	87	88	97	90	7:30 AM	72
6/22	82	77	112	92	101	84	97	88	86	88	104	88	8:30 AM	69
6/23	78	77	104	70	100	84	99	91	89	88	106	88	7:26 AM	60
6/24	76	71	96	68	98	80	92	86	81	78	98	78	7:04 AM	61
6/25	73	71	89	72	90	78	90	85	78	76	86	73	7:40 AM	65
6/26	77	73	85	79	85	80	89	91	81	78	89	78	10:20 AM	75
Ave Temp	97.0	91.8	119.6	81.6	113.6	99.6	115.0	112.0	101.4	102.7	112.6	92.5