Making Your Own Compost: Basics, Troubleshooting, and FAQ

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Compost is one of the best things you can do for your garden soil, especially if you garden organically. It conditions your soil with organic matter, which helps with drainage and compaction problems. It’s also a great slow-release fertilizer, offering the full spectrum of nutrients and important minerals plants need for healthy growth.

You’ll pay a decent premium when purchasing good compost, depending on the sources available where you live. Starting your own backyard compost will offset at least some of that cost, and it’s a great way to reduce waste and recycle a lot of your household trash for use in the garden.

Making your own compost can be as hands-on or laidback as you want. Even if you’re a total newbie, you can learn everything you need to know to get started in a few minutes.   

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Bins, Tumblers, or an Open Pile: Which is Best?

If you’ve read about composting online or just mentioned it out loud within earshot of your phone, you’ve probably seen ads for compost tumblers or bins by now (y’all know what I’m talking about). So, you might be wondering what kind of setup is best for your compost.  

You don’t need to buy a special container or anything else to start composting. You can start a pile on the ground right out in the open, and that’ll do fine. That said, what kind of system will work best for you depends on where you live and what kind of space you have available. 

Contained Systems

Compost bins or tumblers create a tidy appearance, if that’s important to you. Folks who live in HOA neighborhoods or have close neighbors sometimes use these, since it’s less likely someone will gripe about them. They also save a little on space, and the container walls can help retain the heat and moisture your compost needs to break down.  

If you’d rather not drop the money on a compost-specific product, you can use an upcycled container like an old trash can or storage tote for your compost. I’ve also seen some pretty cool designs for DIY compost tumblers made from old barrels or drums. Just make sure to drill plenty of holes in the sides and bottom of your DIY bin(s). You need good airflow to make good compost!

Contained composting systems have a few drawbacks, depending on the type of container:

-If you’re using a tall bin like a trash can, it’s a pain to get a digging fork or shovel in there to thoroughly turn the compost.

-Moisture retention can become a problem instead of a benefit. Compost in a bin or tumbler is more prone to getting overly wet and smelly if the balance isn’t just right.

-Containers don’t allow easy access for earthworms and other beneficial soil dwellers that help the composting process. If you’re using a tumbler or your bin isn’t in contact with the ground, they won’t have access at all.

-If your container is too small, you’ll have trouble getting your compost to heat up. I’ve heard talk that this is a problem with some of those smaller tumblers you can buy.    

Open Systems

An open composting system can be as simple as a free-standing pile wherever you’ve got room, or you can make a little stall or enclosure to keep it semi-contained. I used cinderblocks to build our several composting stations. Some other ideas include straw bales, t-posts and hardware cloth, or open stalls made from scrap wood or pallets.

While an enclosure isn’t a requirement, having “walls” makes turning the compost easier, since it can’t sprawl out as much during the turning process. It also prevents washouts during heavy rain.  

Personally, I think open systems are more forgiving for beginners. They’re easier to manage and less likely to stink, since they’re out in the open air. Plus, easy access for beneficial soil dwellers keeps things going even if you don’t tend the pile perfectly. When life happens, neglected compost on the ground will break down a lot faster than neglected compost in a container.    

Aside from being a potential eyesore, the main drawback to an open compost system is the possibility of your pile hosting rodents. Rats or mice might be tempted to nest in warm compost, during winter. Without a critter-proof container, it can be a challenge to keep them out.  

Compost Ingredients: Greens and Browns

The biodegradable materials you’ll be adding to your compost pile are broken into two categories: greens and browns. You’ll need a balance of both to make the best compost. 

Green materials (which aren’t always green) are things rich in nitrogen. They’re typically your “wet” ingredients, like fresh plant material and kitchen scraps. Some examples of green materials include:

• Fruit and vegetable scraps
• Fresh grass clippings or lawn waste
• Spent coffee grounds
• Manure from grazing animals (cow, chicken, rabbit, etc.)

Brown materials, your “dry” ingredients, are those high in carbon. Brown materials can include:

• Shredded leaves
• Plain (not heavily inked) shredded cardboard or paper products, such as packing paper, paper towels, egg cartons, plain boxes, coffee filters, etc.
• Saw dust
• Woodchips
• Dry yard waste, such as sticks and twigs, pine needles, or dried grass clippings
• Straw
• Old potting soil
• Rinsed, dried, and crushed eggshells (technically, eggshells don’t contain carbon, but they’re rich in calcium and other minerals)

Hot Composting vs. Cold Composting

Based on how much time you want to devote to composting, you can either keep a hot compost pile or stick to cold composting. You’ll get finished compost a lot faster with hot composting, but the pile needs regular attention and work. Cold composting is much more hands-off.

Hot composting relies on high temperatures and the work of mainly aerobic (oxygen-loving) bacteria to break down materials rapidly. A well-tended hot compost pile can reach temperatures of 140 F or higher for days at a time, which effectively kills weed seeds and disease organisms.

In order to heat up a compost pile and keep it up to temperature, you’ll need the right balance of greens and browns. You’ll also need to keep it well-aerated by turning or other methods. When done just right, hot composting can produce finished compost in a month or so. Large piles that get really hot might finish even faster.

With cold composting, you don’t need to worry so much about the ratio of greens to browns. Instead, you just add compostables to the pile and let nature do the rest of the work.

Bacteria, fungi, and other decomposers like earthworms all pitch in to break down a cold compost pile. Depending on the season and what kind of materials you’re adding, a cold pile can take anywhere from several months to a year to finish composting.    

Which Method Makes Better Compost?

Either method will yield nutrient-rich compost for your garden, fruit trees, or flowers, but you’ll notice a few differences in your finished product.

A cold compost pile may shrink a little more than hot compost, depending on how long it takes to finish. The longer it takes, the more it’ll shrink. The finished compost also tends to have more debris, since a cold pile doesn’t break down at an even rate throughout. For certain uses, such as mixing your own potting soil, you’ll probably need to run it through a sieve to remove any large un-composted bits.

Hot composting is a fun challenge and a way to make a lot of compost quickly, for some. For folks without a lot of time, the more laid-back process of cold composting is more manageable.

Some Best Practices for Cold Composting

-Since a cold compost pile doesn’t reach high enough temperatures for fast decay and sterilization, you’re a bit more limited on what you can throw in without risking trouble. Generally, you shouldn’t add seedy weeds, which will definitely sprout at some point (probably in your garden). Also, don’t add diseased garden plants, if you plan to use the compost for next year’s vegetable crops.

-While the greens to browns ratio isn’t as crucial in cold composting, a little balance will keep down odors and help your cold compost pile finish sooner. Keep an eye on how things are going and adjust if needed. If the compost gets sludgy, add some browns. If it looks dry and isn’t changing much, throw in something green.

-To make sure your cold compost pile breaks down evenly, stop adding materials once it reaches a certain size and start a new pile instead.

-An open system is best for cold composting. That way, soil dwelling decomposers and beneficial compost bugs can easily access the pile. Cold compost in a container will take much longer to break down, and it could get pretty nasty in the process.

How to Build and Maintain a Hot Compost Pile

To get an evenly hot pile, you’ll need to build it up as quickly as possible, preferably within under a week. That’ll ensure everything is breaking down at the same rate throughout the process. Follow these steps to get your hot compost pile going:

1. Start with the proper ratios.

From a technical standpoint, you need a 30:1 ratio of carbon (browns) to nitrogen (greens) for a hot compost pile. But since brown materials have less carbon by weight and green materials have more nitrogen by weight, measure them with the following ratio to hit that balance: 3 parts brown materials to 1 part green materials.

When you’re eyeballing those ratios, you might need to adjust for density with certain brown materials. In less science-y terms, one bucket of a “heavy” brown material like woodchips has a lot more carbon than one bucket of shredded paper, so you’ll need less to get the right balance. I use a lot of woodchips in my compost, and I’ve found that one bucket of woodchips to one bucket of greens (1:1) works well.

There’s no need to overthink the ratios, since you can easily adjust things later if something seems off (more about troubleshooting further down).

2. Make sure the pile is big enough.

If your pile is too small, it won’t be able to retain enough warmth. To reach that ideal temperature range for hot composting, the pile should be at least three feet wide by three feet tall.  

3. Once the compost heats up, keep it aerated by turning regularly.

The pile should heat to temperatures over 100 F within a few days to a week. Once the temperature peaks and starts to fall, it’s time to start turning.

If you want to get serious about hot composting, a compost thermometer is an invaluable tool that’ll cost you less than $20. That’ll help you turn the pile when the temperature is just right, which makes the process as quick and efficient as possible. If you’re not opposed to sticking your hand in the compost, you can also just feel the pile to gauge the temperature.  

Wait for the pile to heat up again before each turning. For fast hot composting, you’ll probably need to turn the pile every few days to once per week.

If turning the compost every few days sounds like a lot, you can try this low-turn hot composting method we use. It’s not quite as fast as typical hot composting, but we usually get finished compost in around three months.

4. Don’t let the pile dry out.

A hot compost pile tends to dry out during the heating phase, especially during hot weather. Keep a check on it and hose it down as needed. You want it nice and damp, but not waterlogged.

5. Keep it covered.

If your compost pile gets drenched during a heavy rain, it’ll cool things down. That’s especially true for smaller piles. While it’s not required, throwing a tarp over the pile can help prevent a rainy spell from temporarily interrupting the composting process. It also helps prevent the pile from drying up when the sun is out.

Compost Problems and Concerns

Chances are, you’ll need to make an adjustment here or there throughout the composting process to keep things going as they should. Compost problems are simple to troubleshoot, and some things might not be a problem at all.

Here are a few situations you might run into:

The compost pile isn’t heating.

When your intended hot compost pile doesn’t heat up, it’s either because the green to brown ratio or moisture level isn’t right, or it’s because the pile is too small. If your pile is smaller than 3’ by 3’, you need to make it bigger!

If you pile is plenty big enough, check the moisture level. It should be damp, not soggy or bone dry. Too wet? Add some browns, remove any covering, and stir the pile well to help it air out. Too dry? Hose it down, give it a few days, and add some greens if it still doesn’t heat up.

The compost pile stinks.

Stinky compost happens when anaerobic bacteria take over. These bacteria thrive in low oxygen conditions and produce a dreadful rotten or ferment-y stench. When your compost starts to stink, it means you’ve got an airflow and moisture problem, usually caused by too much green material. To fix it, add more brown materials to absorb moisture and turn the pile.  

The compost isn’t…composting.

If your compost pile is just sitting there and isn’t changing (stinky changes or otherwise), there’s probably too much brown material. Cold compost piles without enough greens will take AGES to break down. A hot compost pile that’s fizzled out may just need more moisture, since hot compost is prone to drying out. If watering doesn’t get it back on track, add more greens.

Bugs have invaded the compost.

Bugs that turn up in your compost are usually just doing their job: helping to break down the organic matter. For hot composting, though, you want those heat-loving aerobic bacteria to be doing most of the work. Seeing lots of bugs may mean the temperature isn’t getting high enough, or your compost pile needs to be turned.

For a cold compost pile, bugs are almost always a good thing. Some friendly compost bugs you might see include pill bugs or sow bugs, soldier fly larvae, springtails, centipedes, earthworms, and millipedes.

One caveat: if you’ve got a horror-movie amount of maggots or soldier fly larvae (which look like large, gray maggots), that’s a sign your compost is overly soggy. You can sometimes just let that phase run its course with a cold pile, if you’re not in a hurry. Or, add some brown material to balance it out and keep things going at a steady rate.

There’s mold growing in the compost.

We’re sort of conditioned to see mold as a sign something has gone wrong. And it is, if it’s in your crawlspace or growing in your tub of yogurt. In compost, though, it’s one of the good guys. Molds in nature assist with the breakdown of organic matter. The type you’ll find in compost are varieties that only feed on dead things; these fungi won’t harm living plants when you use it in the garden.   

Cold compost piles are usually fungal-dominant, meaning fungi play a big role in the composting process. Mold can turn up on hot compost piles, too, especially during wet weather or on newly-added green materials. If you see a ton of mold on your hot compost, though, it might be too wet. Check the temperature and moisture levels to see if adjustments need to be made.

Note: Even the friendly molds that help with the composting process can cause allergies and irritation if you breathe in the spores. It’s never a bad idea to wear a mask while you’re turning or harvesting compost, especially if you’re sensitive to mold.

Some Compost FAQ

What kinds of household waste SHOULDN’T go in the compost?

This depends on how you’re managing your compost. In most cases, avoid meat scraps and bones or cooked foods, since these will attract varmints. Some folks say things like stale bread, cooked pasta, or rice are considered brown materials and are fine to add. However, I’ve found those also attract varmints. In my case, the varmints are my barn cats, who’ve decided stale compost bread is superior to the cat food we spend a small fortune on.

All that said, many people successfully compost all of the above. A large, well-managed pile that reaches reliably high temperatures can break them down before they attract unwanted attention. It’s definitely best to wait until you’re confident in your hot composting process before you try it, though.

Also, be careful about woodchips or leaves from black walnut trees. These native trees are everywhere in some parts of the eastern US, and they produce a chemical called juglone that stunts the growth of many vegetable plants. Proper hot composting gets rid of juglone, but it can take several years to go away in a cold pile.

If you do compost with black walnut material, use caution! A safe bet is to compost it in a separate pile for use on native plants, shrubs, or fruit trees that aren’t juglone-sensitive.

Here are a few things you shouldn’t put in the compost pile under any circumstances:

-Paper or cardboard that’s glossy or heavily inked, like magazines or cereal boxes. A little ink like a brand or product label is fine (my personal opinion).  

–Packing material that contains plastic or Styrofoam. Give packing inserts a good inspection before adding to compost, since some contain padding that isn’t biodegradable.

-Tea bags. I used to put a lot of used tea bags in my compost, until I found out most contain nylon fibers and microplastics. Don’t add them unless you know it’s a plastic-free brand!

-Sawdust or scraps from treated lumber. Treated lumber contains chemicals that prevent rotting (the opposite of what you want in compost). Plus, you don’t want those chemicals in the soil where you’re growing your food.

Can you compost diseased garden plants?

It’s fine to put your blight-ridden tomato plants in a hot compost pile after harvest, if you know that pile will reach temperatures of 120 or higher for several days. Otherwise, pathogens may survive the composting process and contribute to future blight problems.

We compost tomato plants and other finished vegetable plants separately for use on our berry bushes and perennials. 95% of the time, perennial plants don’t share diseases with annual vegetables. The exception is certain root and crown rots. If you had veggie plants that suffered from some mysterious root rot or wilt condition, those are best reserved for the fire pit.  

Will a compost pile attract critters?

The woods on our property joins national forest not far away, so we have lots of coons, opossums, and even bears in the area. Nothing ever bothers our compost, as long as we don’t add any of the no-no’s like cooked foods or meat scraps.

Even if you follow those best practices perfectly, your nice, warm compost pile might still attract mice or other rodents if you don’t have a barn cat on duty. You can try trapping the mice, if there are only a few. If it becomes a constant problem, consider a lidded enclosure for the compost, such as a wooden frame with hardware cloth.

Is compost still safe to use if mice or rats got into it?

Finding mice or signs of them in your compost pile doesn’t mean the compost is contaminated or ruined. Yes, they can carry diseases, but mice and rats are all over the place. We’re not dropping like flies from going outdoors or occasionally finding an uninvited guest in the house.

If you see mouse signs in your compost pile, just follow the same basic precautions you’d use for mold. Wear a mask when messing with the compost, wash hands after handling, and wash produce from the garden before you eat it.   

Can you put spoiled or moldy produce in the compost?

Forgot about something in your fridge, and now it looks like a fuzzy science experiment? That’s perfect for the compost, since the process is already underway. Honestly, nothing is too far gone for the compost.

How to Cure and Use Your Finished Compost

First of all, how do you know when the compost is done? Finished compost feels soft and crumbly like soil, and it should smell earthy and pleasant. You shouldn’t see too much recognizable “stuff” in the finished product (a few bits here and there is fine).

Cold compost piles will have more un-composted things, even when you’ve got finished compost ready to harvest in the middle of the pile. Also, if you add lots of eggshells, those take FOREVER to completely disappear. I usually see plenty of eggshell pieces in my finished compost, and I just let them finish breaking down in the garden.

Some prefer to sift out unfinished bits and put them back in an active compost pile. Since I use no-till gardening methods that involve layering the finished compost on top of the soil, I don’t fool with that unless I want to use my compost for potting mix.

Can you use finished compost in the garden immediately?

If you’re hot composting, the finished compost ideally needs to cure for a while before you use it in an area you’ll be planting soon. Compost that’s still too active can sometimes burn plants. The pile should rest for a month or so to cool down. If you’re amending your garden before winter or you’ve got some time before you’ll be planting, you can go ahead and spread it right away.   

Making homemade compost is a simple and flexible project. Once you know the basics, you can find a groove that works for you. You might not be able to make enough compost to supply all your garden’s needs (we sure can’t!). Still, it’s always worthwhile when you can close a loop and make your household and garden a little more sustainable.

If you’re a small family that doesn’t produce a lot of compostable waste, or if keeping a dedicated compost pile isn’t practical for you, you’ve got other options. Look into trench composting as an alternative to make use of what you have.