Best Compost Bin for a Small Backyard: Types and Sizes

The Best Compost Bin for a Small Backyard, by Situation

For most small backyards the best compost bin is an enclosed plastic bin that sits on soil: you load it from the top, take finished compost from a door near the base, and it is made for small to moderate spaces. Choose a tumbler instead if rodents are a concern or you do not want to turn material with a fork. Choose a worm bin if you have kitchen scraps only and no bare ground. If you can spare a full 3 by 3 foot corner and want fast compost, a 3 x 3 x 3 foot holding bin is the smallest size that heats up properly.

That short list covers nearly every tight yard. The rest of this page explains the types, the sizes, and how to work out which line fits you.

Types of Compost Bins

Extension guides sort home compost structures into a few families, and the names on product listings map onto them.

Holding units are the simplest. Material goes in and stays until it is done. A wire-mesh cylinder made from a 10-foot length of 36-inch-wide fencing is a holding unit. So is a bin built from four wooden pallets, and so is the familiar molded plastic bin with a lid on top and an access door near the bottom. A lidded garbage can with holes drilled 4 to 6 inches apart around the sides is the smallest version.

Turning units are built for mixing. A tumbler is a single drum on a frame that you rotate, and the classic homemade version uses a 55-gallon drum. A three-bin system does the same job on the ground: you fork material from one bay to the next, and each bay is about 3 x 3 x 3 feet. Three bays need a strip about 9 feet long, which rules them out of most small yards.

Worm bins use red wigglers in a shallow box. They are sized for kitchen scraps, and a wheelbarrow of leaves will not fit. A common starter size is 1 foot deep, 1 foot wide and 2 feet long.

In-ground options include cone digesters, which process kitchen scraps in a small space, and plain trenches dug in an empty bed.

Bin type	Typical size	Takes yard waste	Rodent resistance	Effort
Enclosed plastic holding bin	Varies by model, built for small to moderate spaces	Yes	Good if every gap is 1/4 inch or smaller	Low, optional forking
Wire or pallet holding bin	3 x 3 x 3 feet	Yes	Low	Low to medium
Tumbler	One drum on a frame, such as a 55-gallon barrel	Small amounts	High	Low, spin when you add material
Three-bin turning unit	Three bays, each 3 x 3 x 3 feet	Yes, large volumes	Low	High
Worm bin	1 x 1 x 2 feet	No, kitchen scraps	High indoors	Low, feed 2 to 3 times a week

What Size Compost Bin Do You Need?

Size depends on whether you want the pile to heat up. Hot composting needs mass. University of Maryland Extension puts the minimum at 3 feet by 3 feet by 3 feet, or 27 cubic feet, and Texas A&M calls 3 x 3 x 3 feet the ideal size for a holding bin because anything taller or wider than 3 feet gets too little air in the middle. Do not stack material more than 5 feet high, since the weight compacts the pile.

Most bins sold for small yards are well under 27 cubic feet. They still make compost. They work at the cool end of the range, 40°F to about 110°F, and take longer. That matters for one practical reason: a small, cool bin does not get hot enough to kill weed seeds or plant diseases, so keep seedy weeds and blighted tomato vines out of it. Hot vs. cold composting covers the difference.

Use these rules to size a bin:

1. Kitchen scraps only. Weigh your scraps for one week. A worm bin needs 1 cubic foot of space for each pound of kitchen waste per week, so a 1 x 1 x 2 foot bin (2 cubic feet) handles 2 pounds a week. A slightly larger tray, 21 inches by 15 inches (about 2.2 square feet), handles 2 to 3 pounds a week.
2. Scraps plus a little yard waste. An enclosed plastic bin or one tumbler is enough. Remember that browns take space too: the pile wants at least two to three times as much dry brown material as green scraps by volume.
3. Scraps plus regular leaves and trimmings. Go to the full 3 x 3 x 3 foot bin. A smaller one will fill in a single fall weekend.

Bigger is not better in a small yard. A large bin that never fills stays cold, and it costs you ground you could plant.

How Fast Each Bin Makes Compost

Speed follows heat and attention more than brand or shape. A well-maintained backyard pile is finished in about three to five months, and it should then cure for at least four weeks before use. Left untended, the same material may take a year. A hot pile of at least 27 cubic feet, turned on schedule, can produce a harvest in six to eight weeks, and an insulated hot bin often finishes within 4 to 8 weeks in a small footprint. Worm bins yield castings after three to six months.

Tumblers deserve a caution. Some are sold with a promise of compost in a few weeks, but Washington State University Extension notes that the material typically takes longer, because the small volume does not hold enough heat. If you add scraps daily, the drum never gets a chance to finish. Two tumblers, or one drum with two chambers, solve this: fill one side, then let it work while you fill the other.

Tumbler vs. Stationary Bin in a Tight Space

A tumbler is sealed and raised off the ground, so it helps keep rodents and raccoons out. You mix by rotating the drum several times whenever you add material, with no fork and no bending into a pile. It can stand on a patio or pavers. The limits are capacity and bulk: a drum does not swallow a pile of fall leaves, and the frame adds to the footprint.

A stationary plastic bin holds more for the ground it covers and takes bulky material through a wide top opening. It sits on bare soil, which gives drainage. Its weak point is pests when food scraps go in. The Environmental Protection Agency advises reinforcing a bin with a lid and potentially a floor, and says it should have no holes or gaps larger than 1/4 inch. Check the base and the harvest door of any bin against that 1/4 inch rule before you buy, and hold any floor you add to an open-bottomed bin to the same limit.

For a wider look at models and features, see compost bins for a small vegetable garden and worm composting bins.

Where to Put a Bin in a Small Yard

Pick a spot you can reach all year that drains well, with a hose or tap nearby. A pile breaks down in sun or in shade, so there is no need to give up your sunniest 9 square feet. The same guidance says to avoid placing it right up against a fence, so leave a gap behind it.

Leave room to work. A plastic bin needs space in front of the harvest door for a shovel, and a tumbler needs clearance for the drum to spin and for a tub or barrow under the hatch.

No ground at all? A worm bin can live under a sink, in a closet or in a basement, or outdoors in the shade, and composting at home without a yard walks through the indoor options.

Mistakes That Make Small Bins Smell

Most complaints about small bins come from loading them with kitchen scraps alone. Keep a bag of dry leaves or shredded cardboard beside the bin and add two to three times the volume of browns every time you add greens. In an open or stationary bin, cover fresh food scraps with four to eight inches of browns. The brown to green ratio and why a compost pile smells go deeper on both.

Keep meat, fish, bones, dairy, fats, oils and pet waste out of any backyard bin, whatever its style. Moisture should feel like a wrung-out sponge. A sealed tumbler tends to run wet because nothing drains away, so add extra browns there, and an open wire bin tends to run dry in summer.

Quick recap

• For most small backyards, an enclosed plastic bin on soil is the best all-round choice; pick a tumbler for rodent pressure and a worm bin for scraps with no ground.
• Hot composting needs at least 3 x 3 x 3 feet (27 cubic feet). Smaller bins work cool and slow and will not kill weed seeds.
• Size a worm bin at 1 cubic foot per pound of kitchen waste per week.
• Expect three to five months from a maintained bin and about a year from a neglected one.
• Close every gap wider than 1/4 inch and add two to three parts browns for each part greens.