Why Isn’t My Compost Pile Heating Up? 7 Things to Check
You build a compost pile, add kitchen scraps, yard waste, manure, and plenty of enthusiasm — then check it a few days later and discover...
Nothing.
No heat. No steam. Just a suspiciously organized pile of decomposing stuff.
We ran into the same problem at Hideaway Homestead Ranch while learning how to make hot compost. Our pile was breaking down, but it wasn't generating the kind of heat we were hoping for.
After experimenting with the mixture, adding horse manure, adjusting the moisture, and turning the pile, we finally started seeing the temperature climb.
If your compost pile isn't heating up, here are seven things worth checking before declaring your compost microbes lazy.
1. Your Compost Pile May Be Too Small
A compost pile needs enough mass to hold onto the heat generated by microorganisms.
Very small piles can still decompose, but they tend to lose heat faster than larger piles.
For hot composting, having enough material together helps create an insulated center where microbial activity can really get moving.
If your pile is little more than a few layers of kitchen scraps and leaves, you may simply need to add more material.
The goal isn't to build Mount Compost, but you do need enough volume for the biology inside the pile to maintain heat.
2. You May Need More Nitrogen
One of the biggest lessons we learned with our own compost pile was the importance of nitrogen-rich material.
Our pile began heating much more noticeably after we added horse manure.
Nitrogen-rich compost materials — often called "greens" — include things like:
- Fresh grass clippings
- Kitchen scraps
- Fresh green plant material
- Coffee grounds
- Animal manure from appropriate herbivores
- Fresh garden waste
Carbon-rich "brown" materials include:
- Wood chips
- Dry leaves
- Straw
- Sawdust
- Cardboard
- Small woody material
If your compost contains too much carbon and not enough nitrogen, decomposition can move painfully slowly.
The microbes haven't gone on strike. They may simply be hungry.
3. The Pile Might Be Too Dry
Microorganisms need moisture to break down organic material.
If the center of your compost pile is dry, microbial activity can slow dramatically.
When we turn our compost at Hideaway Homestead Ranch, we add moisture as we rebuild the pile. Recently we've been using rainwater collected on the property rather than using fresh stored water whenever possible.
The material should generally feel moist throughout without being completely saturated.
Think damp sponge rather than backyard swimming pool.
If you turn your pile and discover dry pockets inside, add water gradually as you're mixing everything together.
4. Or Your Compost Could Be Too Wet
More water isn't always better.
If the pile becomes completely saturated, water can fill the air spaces between materials and reduce the oxygen available to aerobic microorganisms.
That can slow decomposition and sometimes create unpleasant smells.
This is one reason bulky materials like wood chips can be useful. They help maintain structure and airflow instead of allowing everything to collapse into a dense wet mass.
If your compost feels soggy or smells sour, adding some dry carbon-rich material and turning the pile may help restore balance.
5. Your Compost May Need More Oxygen
Hot composting relies heavily on aerobic microorganisms — microbes that require oxygen.
As organic material settles, the center of a compost pile can become compacted and oxygen levels can decline.
That's where turning the compost pile becomes useful.
Turning mixes the ingredients and introduces fresh air into areas that may have become compressed.
When we finally got our pile heating up, turning it was an important part of the process.
It also gave us a chance to see what was actually happening inside the pile instead of trying to diagnose everything from the outside.
6. The Ingredients May Not Be Mixed Well
Layering compost materials is useful when initially building the pile, but eventually those ingredients need to interact.
If one area contains mostly wood chips while another contains mostly manure or kitchen waste, decomposition may happen unevenly.
Turning helps redistribute:
- Nitrogen-rich material
- Carbon-rich material
- Moisture
- Microorganisms
- Oxygen
Our compost contains a mixture of materials collected around the homestead, including wood chips, manure, kitchen scraps, green plant material, old soil, and unfinished material from previous compost.
Mixing those ingredients together gives the microorganisms access to a much more balanced buffet.
Tiny compost organisms apparently appreciate menu variety.
7. You Might Not Actually Know How Hot It Is
This one sounds obvious, but it's surprisingly useful.
The outside of a compost pile doesn't always tell you what's happening in the center.
That's why we started using a compost thermometer.
A long-probe thermometer lets us reach deeper into the pile and track how the internal temperature changes after:
- Turning
- Adding manure
- Adding water
- Rebuilding the pile
- Leaving the pile undisturbed
Instead of guessing whether something worked, we can actually measure the result.
Compost Thermometer We Use
We're using a REOTEMP Backyard Compost Thermometer to monitor our pile.
See the REOTEMP Compost Thermometer on Amazon (paid affiliate link)
For us, the thermometer has turned composting into more of an experiment.
Make a change.
Measure the temperature.
Watch what happens.
Adjust again.
That's a much better way to learn than repeatedly poking the pile and confidently announcing, "Yep, still compost."
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What Finally Made Our Compost Pile Heat Up?
Our biggest improvement came after adding horse manure, turning the pile thoroughly, and making sure the material had adequate moisture.
Soon afterward, we started seeing noticeably higher temperatures.
That doesn't mean horse manure is some magical compost ignition switch.
The more likely explanation is that our pile needed a better balance of nitrogen, moisture, oxygen, and microbial activity.
Adding manure helped move that balance in the right direction.
We cover the entire experiment in our main hot-compost article:
Read: How We Finally Got Our Compost Pile Hot
And you can watch the actual pile being turned and tested here:
Watch: Making Hot Compost at Hideaway Homestead Ranch
Composting Is About Managing Biology
One thing we're beginning to understand is that making compost isn't really about "making dirt."
We're managing an ecosystem.
Bacteria, fungi, insects, moisture, oxygen, carbon, and nitrogen are all interacting inside the pile.
Our job is mostly to create conditions where that biology can do what it already knows how to do.
That's part of why composting fits so naturally into the direction we're taking Hideaway Homestead Ranch.
Instead of constantly bringing fertility onto the property, we want to learn how to cycle more of the resources already available here.
From Compost to Soil Health
The finished compost from these piles will eventually go back into our garden beds and other growing areas.
Over time, adding organic matter can help us improve the soil we're working with rather than simply replacing it with purchased soil every season.
That's also where our little compost experiment begins connecting to much larger ideas around soil health and regenerative agriculture.
As we eventually add livestock to the ranch, manure can become part of that nutrient cycle.
Animals produce manure.
Manure goes into compost.
Compost helps improve soil.
Healthier soil supports plants.
Plants can eventually help support animals.
Those interconnected systems are exactly what we want to learn how to build.
Don't Give Up on a Cold Compost Pile
If your compost isn't heating up, it doesn't necessarily mean you've failed.
Cold compost still decomposes.
Hot composting simply speeds up the process and gives you another way to actively manage what's happening inside the pile.
Check the basics:
Is the pile large enough?
Does it have enough nitrogen?
Is it moist?
Is it too wet?
Does it have oxygen?
Are the ingredients mixed?
And are you actually measuring the temperature?
Make one adjustment at a time and watch what happens.
That's exactly how we're learning.
Support Our Homestead
Building Hideaway Homestead Ranch is a long-term project, and sharing what we're learning along the way is a big part of the journey.
If you enjoy following our experiments with composting, gardening, off-grid systems, livestock planning, and building the ranch from the ground up, you can support us on Patreon.
Patreon members help us continue creating videos, experimenting with new systems, and sharing the process as Hideaway Homestead Ranch grows.