Do you find yourself wondering, “why did my compost pile not work?” You’re not alone.

Many of us have started composting, only to find it didn’t work out the way we hoped. We gather garden refuse and kitchen scraps and rake up some leaves, confident we’ll soon have our own supply of garden magic, only to find it just sits there. We finally forget about it, and it grows a dandy crop of weeds. 

Composting is really just encouraging natural processes to happen in a bit more energetic way. We want decomposers to chew up, eat, and recycle our piles into plant-nourishing dark, earthy goodness. While the conditions for composting are simple, ignoring one can slow down the whole endeavor and cause discouraging delays.

What Compost Is (and isn’t)

Compost is decomposed organic material, in other words, stuff that was once living. For simplicity in home compositing, we avoid meats and prepared foods, which can invite pests and cause other issues. When gardeners talk about compost, we’re excited about the good-as-gold soil amendment, which includes humus, plant-available nutrients, and a strong helping of good soil microbial life. 

It’s worth mentioning that compost isn’t fresh manure, a pile of rotting leaves, or a stinky mound of molding kitchen garbage. Finished compost is dark, friable, and feels good in the hand. There is no unpleasant odor, no sliminess, or offputting characteristics. Finished compost should be crumbly and dark, with few to no identifiable remains of the materials that were feedstock for the pile.

The Often Ignored Composting Basics

The process of composting requires the action of decomposers, whether insects, worms, fungi, bacteria, or others. Those decomposers, particularly the smaller ones like the trillions of good bacteria that break down carbon-based materials (plants), function best when conditions are right and they are comfy. They slow down or stop altogether when one of their needs isn’t met. When they stop working, so does your compost pile.

Moisture

Adequate moisture might be the most commonly ignored requirement in home compost piles. We instinctively know that wet conditions cause something to rot faster, but why? The microbes that do the heavy lifting of composting all need a little moisture to thrive. As the pile dries out, they have a tougher time, and decomposition is slowed. 

We often don’t get enough rain in summer and fall to keep things moving at the optimum pace. A compost pile should be moist but not soggy. If you grab a handful of material, it should feel like a damp sponge; if you squeeze it, a drop or two of water should fall out.

If it hasn’t rained in a few days, check your pile when you walk by and give it a good shot with the hose if needed. Compost piles in warm, dry weather can need watering weekly.

Too much moisture can eventually be a problem, causing anerobic conditions and fostering the wrong kind of bacteria, but it’s not normally much of a problem unless the weather has been extra damp. If your pile is saturated, try loosely covering it with a tarp for a while to shed some rainfall. Once it’s back to the merely damp stage, uncover it again.

Air flow

Good bacteria and other microbes need oxygen to work, and they can’t get it if the pile is compacted and dense. The bacteria we want are aerobic, meaning they function in the presence of oxygen. Aerobic bacteria happily change plant wastes into nutrients and humus. Without oxygen, the process is slower, and anaerobic bacteria often dominate and can cause a foul odor and the release of methane. They’re also much slower.

The normal solution is to aerate or turn over the pile every couple of weeks, giving it a good stirring up, but that can be a lot of work. A good mixture of particle sizes when building the pile can achieve much of the aeration needed. For example, a pile of grass clippings or coffee grounds from your local shop would be dense and have poor aeration. But, adding broken twigs, dry leaves, and broken-up straw to the mix will change the texture, allowing pockets for air to move about.

Temperature

The temperature of your pile will dictate how fast or slowly it turns from yard and garden waste into compost. Just like seeds have a preferred temperature to germinate, bacteria and decomposers work better in warmer temperatures. It’s why refrigeration keeps food from spoiling quickly. Those little microbes are still present in cold temps but are not as active. 

Locating your compost pile in a sunny location can help it warm up, and the size of your pile will also factor in. A large pile will have more microbial activity and, therefore, more warmth than a small one. If you are curious about the temperature of your pile, long stainless steel compost thermometers are fairly inexpensive. 

Mass and particle size

It’s hard to compost a tiny pile effectively. A five-quart ice cream pail of scraps in a mound outside will take a long while to break down because it never warms up and gets some steam going. In general, the larger the pile you can accumulate, the more likely it will begin to warm up and do its thing, all else equal. 

To speed up your composting, scrounge around for more feedstock. Ask neighbors, local food stores and co-ops, or snag bags of leaves in the fall. A pile that starts at about 3 feet on each side and is 3-4 feet tall will have enough material to heat up nicely.

Particle size is also a big player in composting efficiency. Large, woody debris takes a long time to break down, just like a forest floor covered with logs and big branches. Some material can take years. Smaller particles have more surface area per unit volume, creating much more area for microbes to attack and start their work. Of course, we don’t want to turn everything into sawdust and lose aeration, but chopping up weeds and veggies into small pieces, breaking sticks, and even chipping woody material can greatly speed up the processes.

Easy Ways to Increase Composting Efficiency 

Water your compost pile

Most compost piles run too dry. Snag the hose and give it a good dousing once a week in the summer, right before you stir it up. If you don’t like sticking your hand down inside the pile to check the moisture, keep a garden fork leaning nearby to grab a sample and look at it. You’ll be able to tell if it is dry or wet.

A quick shot of water at the top may not be enough, so get into the middle of the pile and feel around. Remember, it should feel like a damp sponge.

Stir compost instead of turning it over 

I’ll admit, I don’t always get out there, grab the fork, and completely turn over my compost pile. I have several, and it’s a lot of work sometimes. But, you can get a lot of the benefit from just stirring it up a bit. Any number of fancy tools are sold to help you aerate and stir up your compost pile without actually flipping it. Even a long, stout stick can be stabbed in and stirred about, aerating and mixing.

Mow feedstock materials

Your lawnmower is an easy way to chop up compostable materials. Leaves, garden waste, etc., can all be broken down by running the mower over them a few times, then raking them up and tossing them in the pile. It also does a nice job of mixing up different items. 

Make a multi-bin compost setup

The trouble with a single pile is you’re always adding to the top, and it feels like it’s never finished. With a bit more work, you can create a multiple-bin compost system. Mine is made out of a few recycled wood pallets screwed together. Once the bin is full, I stop adding to it and start putting new feedstock in the next one. By the time I get the third bin full, the first is normally nearly done and ready to use. 

Using multiple piles or bins also makes it easier to gauge how much has rotted down and to aerate or flip without a constant addition of new material on top.