Nothing is more satisfying than turning organic scraps into usable composting material for your vegetable garden. Composting is a natural and nutrient-rich soil amendment process that helps the environment by reducing household waste and is a great way to keep your garden running at its peak. But how long does it take to make compost?
Hot composting is the fastest way to make compost taking as little as a few weeks to months, depending on your pile’s size and ideal conditions. However, hot composting is very hands-on, requiring more attention and effort to create. On the other hand, cold composting requires minimal effort and is the slowest, most natural way to make compost. Cold compost generally takes 6 to 18 months (or more) until it is ready to use.
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So how long does it take to make usable compost under your conditions? It comes down to your chosen method, each taking a different amount of time. Generally, the time it takes to create usable compost depends on the size and type of raw materials used, how often the pile is turned, the temperature, moisture content, and where the compost is located and stored.
Have you never composted before? Or perhaps your pile isn’t breaking down as fast as it should. This article will help you start composting in a simple, effective way. By understanding the process of hot and cold composting, the various factors that influence each, and some extra humble tips that can speed up the entire process, you’ll be well on your way to success. So, let’s start composting!
- Discover how to perfectly balance your compost heap with the correct carbon to nitrogen ratio, so you can have a pile that decomposes quickly and efficiently.
- Stop worrying about how your compost is forming by unlocking these 7 proven ways to help you get your compost back on track in no time!
- Save time by knowing how to manage your compost pile AND learn these innovative and simple tips for both hot and cold composting techniques so you can determine which method is best for you!
How Long Does Compost Take To Break Down
Generally, compost can break down anywhere from several weeks to two years. On average, compost takes about six months to be ready for use as an amendment to your vegetable garden under the right conditions. The larger your compost pile, the moisture it retains, the temperature is maintains, and how often you aerate it all help quicken the process.
Of course, as you may already know, finished compost isn’t soil, even though it appears similar. Instead, mature compost, called humus, supplements your vegetable garden’s overall health, care, and maintenance.
Also known as black gold to seasoned growers, compost is the perfect addition to garden soil to enhance your beds’ nutritional quality and texture to where your plants call home. Whether you are planting within an established garden area or carving out a new spot, the nutrients in compost help the ground retain moisture, encourage healthy root growth, and provide happy plants and excellent harvests. 1
The Composting Process
Composting is a natural process of breaking down organic materials into nutrient-rich soil called compost, also known as humus. This process, facilitated by microorganisms like fungi, bacteria, and actinomycetes, breaks down the materials forming compost that you can reuse within your vegetable garden.
This decomposition process of compost accelerates by providing oxygen to your pile when actively turning the pile with a shovel or garden fork. This aeration process is crucial because it helps oxygen reach the microorganisms responsible for breaking down the materials in your compost and speeds up decomposition. Moreover, added moisture helps keep these microbes alive and active as they work within your compost heap while encouraging more microbial activity.
Finally, ensuring the proper temperature within your compost mound is essential to how quickly you will have usable compost for your garden’s vegetable plants. 2
There are several critical stages of decomposition in composting, each with its uniquely helpful characteristics.
The Mesophilic Stage
The initial composting phase is called the mesophilic stage. Here, you’ve added the essential, raw components of nitrogen (greens) and carbon (browns) within your pile, ready to be composted. In doing so, you’ve created the perfect environment for the microorganisms mentioned above to begin working by initiating decomposition within your pile.
Once this army of bacteria, fungi, and worms begins chomping away at your pile, they create a lot of energy, also known as metabolic activity. And, as a byproduct of all this elevated activity, comes heat. Thanks, high school biology!
All of this metabolic activity (heat) created by the microbes may raise the temperature of your compost pile to as high as 120°F to 130°F (approximately 49 to 54°C) within just a few days, depending upon your pile’s current conditions and regional climate. In addition, as temperatures increase, organic acids will also be introduced, lowering the pH within your compost heap.
Heat is vital for compost to decompose quickly. That’s why gardeners say their compost pile is “cooking.” It’s simple garden jargon, meaning they expect to have usable compost for their veggie plants sooner rather than later.
The Thermophilic Stage
The next step in the process is called the thermophilic stage. During this phase, the compost temperature rises from 150°F to 175°F (approximately 65-80°C), which sanitizes and further reduces the compost pile volume.
In the thermophilic process, the decomposition activity in your pile reaches a fevered pitch. The microorganisms in the last phase are replaced by more heat-tolerant and complex ones called thermophiles. For the next few weeks to months, these thermophiles degrade more complex proteins and carbon sources while changing the environment within your compost pile to a more alkaline pH.
Additionally, during this high heat phase, a pasteurization period commences where harmful bacteria such as Salmonella or E-coli that may be present will die.
It’s best to keep your compost pile well-ventilated throughout the thermophilic stage. Turning your heap at least once weekly means you are affording needed oxygen to the microorganisms working hard on your behalf who are systematically decomposing and sanitizing your pile.
The Cooling Stage
The cooling stage is a short process where nitrogen and carbon have effectively broken down. Additionally, the temperature in your pile lowers, and the mesophilic microorganisms from the first stage reappear to finish any remaining decomposition.
The Maturation Stage
The final step of compost decomposition is called the maturation stage. At this point, the pile’s temperature continues cooling while becoming more stable as additional reactions transpire.
Although decomposition is still occurring during this state, it’s much slower due to the decreasing temperature. The maturation phase can last a few weeks or even several months, depending upon the type of organic material in the pile, the amount of moisture and oxygen incorporated, the size of your mound, and its ambient temperature.
As the maturation stage concludes and the temperature stabilizes, a dark, loamy, and earthy medium remains. This mature compost, known as humus, is the final result that Mother Nature recycles for your benefit.
But hold up for just a moment. Now that the process is complete, how do you know how much compost to apply to your vegetable garden and how often to apply it? Fortunately, I wrote an entire article about this, along with some other goodies that will get your vegetables off to a quick and healthy start.
What Is Hot Composting And Why Is It Effective
Hot composting is the fastest way to make compost but also the most time intensive. Hot composting is an aerobic process that regularly incorporates oxygen throughout your compost. Besides adding moisture, microorganisms will heat up and break down the pile quickly and efficiently, resulting in compost within a few weeks to months.
Hot composting gets its name from the heat generated during this method. Hot composting requires a 3:1 ratio of three parts browns (carbon) to one part greens (nitrogen) while also integrating oxygen and moisture into your pile. 3
It’s important to understand that if the brown-to-green ratio becomes unbalanced in your pile, so to becomes your compost, and challenges may arise. For example, suppose there is an overabundance of greens (nitrogen), a common issue many composters face. In that case, the microorganisms will decompose the carbon but release a surplus of nitrogen into the environment as ammonia which can cause an unpleasant and smelly situation.
On the other hand, if your pile has excess carbon (browns), you won’t provide the microbes with the necessary food to do their work and break down your pile correctly. As a result, their numbers dwindle markedly, and your pile ceases to decompose. If not corrected, your pile could remain inert for months on end.
An example of green compostable materials are:
- Food waste, such as fruit and vegetable scraps
- Grass clippings (so long as your yard isn’t treated with synthetic chemicals)
- Green leaves
- Coffee grounds and tea leaves/bags
- Weeds that have not gone to seed
- Aged manure from herbivorous animals, such as cows and horses
- Green plant trimmings, such as pruning from shrubs and bushes
It’s important to note that not all green materials are suitable for composting. For example, avoid adding fats, oils, and dairy products to your compost pile. Likewise, although some gardeners throw in meat scraps and bones, I also suggest avoiding these as they attract unwanted visitors and pests like rats, squirrels, and raccoons.
Likewise, I suggest you avoid tossing diseased plants and mature weeds that have gone to seed in your heap. And even though your compost’s hot temperature may kill the disease and weed seeds, I suggest you throw these out rather than take a chance by inadvertently transferring your finished compost into your garden. Again, I suspect you’d rather avoid a situation where disease potentially spreads from your compost pile to your plants once you’ve transplanted it into your vegetable garden.
Examples of brown compostable materials are:
- Dry leaves
- Straw, hay, or sawdust
- Shredded paper and cardboard
- Cardboard egg cartons
- Cotton and wool rags
- Wood chips or shavings
- Small sticks, branches, and twigs
The short video below is a great resource that helps you understand the different composting methods and techniques available to gardeners and when to know when compost is ready to be used throughout your green space.
What Is Cold Composting And Why Is It Effective
Cold composting is considered the lazy man’s way of making compost, as it can take anywhere from 6 months to 18 months (or more) for the pile to decompose sufficiently. This composting is an anaerobic process where the pile is not turned, resulting in little to no airflow or oxygen. As a result, the temperature does not sufficiently increase, and the heap normally decomposes over time through fermentation.
As in hot composting, with cold composting, you add raw materials to your heap. However, unlike the previous process, cold composting is a hands-off procedure, as you don’t turn your pile to provide oxygen to the microorganisms. Instead, nature takes its course and allows the ingredients to decompose naturally.
Conditions for cold composting are straightforward. First, you can avoid frustration from getting your compost pile to heat up and “cook.” It also means less off-gassing of nitrogen and carbon dioxide as your pile stays at more moderately consistent temperatures.
Aside from the minimal effort of physical effort required already mentioned, cold composting is a more flexible process that includes many beneficial microorganisms that enjoy and thrive in milder conditions. Adding these microbes to your vegetable garden is helpful to your plants since it’s these same organisms your plants need to stay healthy and stave off disease. 4
No matter the composting method, I recommend you have at least two compost heaps – one that is actively composting and processing and the other in which you continually add your browns and greens. Multiple heaps will help speed up your compost and provide better quality as you aren’t overworking your microbial life. Plus, you’ll always have available compost for the garden.
What Will Make Compost Break Down Faster
You can do several things to speed up the decomposition of your compost pile for faster results. The most common helpful ways are adding ventilation, increasing your pile size, decreasing the size of the raw materials you include, and keeping your pile wet but not saturated.
Getting the conditions right in your compost is more art than science. So don’t become discouraged if you can’t get the essentials correct at the beginning to get your compost heap “cooking.” Instead, stick to the basics and remember the best practice is more practice. Remember, you can never truly go wrong when composting because nature will inevitably run its course and break everything down accordingly.
Balance Your Greens To Browns Ratio
There is much debate about what amount of browns to greens you need for effective composting. However, through much trial and error, if your ratio of 3:1 browns (carbon) to greens (nitrogen) is unbalanced, you will have difficulty getting your compost to, well, compost. Because a healthy compost heap always has more carbon than nitrogen, I recommend you observe and smell your pile often, especially as the decomposition process begins.
Many new composters notice their compost pile smells, becomes slimy, and isn’t breaking down appropriately. The likely culprit is that more greens (nitrogen) than browns (carbons) have been incorporated, thereby throwing off your ratio. This problem can occur anywhere but tends to happen more frequently in urban environments with limited carbon (brown) materials. The simple fix is to amend your pile by mixing in more browns and reevaluate.
Add More Air
For better overall decomposition, offer more ventilation to all those worms, bacteria, and fungi working so hard to bring nutrient-rich “gold” to your vegetable garden. While the average may be turning your pile once every 4 to 6 weeks, you can cut this in half and do it every 2 to 3 weeks or more if you are looking for a faster result.
However, remember that more turning means more disruption to the heat your compost pile generates. As a result, you can disturb and slow the composting process, which may not provide enough sustained heat to kill some harmful microbes or weed seeds. 5
To avoid this interference, an easy step to continually provide air to your compost is by placing a foundation of sticks and branches at the very bottom and layering your compost on top. These branches offer additional nutrients as they break down and create a continuous flow of air from the ground up that helps speed things along, provides welcome drainage, and may even eliminate the need to turn your pile as frequently.
When in doubt about your composting efforts, or if you are looking for further resources, be sure to check your state’s Department of Health. They may have additional information that can be useful to your composting method in your local area.
Add More Moisture
Failing to add the right amount of water is a common cause of unsuccessful composting and is essential if you want to keep your microorganisms content and active within your heap. Less moisture leads to fewer microbes in your compost pile, leaving you stuck with an underperforming or, at worst, unresponsive mess. Conversely, adding too much water creates a stagnant environment, effectively stunting decomposition.
A healthy compost pile should feel moist in your hand, not saturated. If your pile feels and looks dry, add water and turn your heap to incorporate the added moisture effectively. If your pile looks saturated, add more newspaper, cardboard, or pelletized horse bedding that will help absorb excess water.
Remember, building a high performing compost pile is an art. It takes time and a bit of practice.
Increase Your Pile Size
The smaller your pile, the more issues you may have within your compost. So, to heat your pile efficiently, you need to create a bigger one. It’s like building a larger fire because you want the added benefit of warming more people. The concept is the same here. You want to invite as many microorganisms to the party as possible to heat your materials and kick off decomposition.
Chop Raw Materials More Finely
It’s best to avoid chucking large kitchen scraps or yard waste in your compost before at least breaking them down a bit. Instead, chopping your kitchen scraps, shredding your cardboard, and cutting twigs or plants with garden shears ensure a healthier environment. Likewise, it also makes for a faster composting process, as the microorganisms won’t have to work as hard processing smaller materials.
You can add worms, especially Red Wrigglers, into your pile to aid in a faster breakdown of your materials. However, if opting for a hot composting environment, avoid adding worms during the thermophilic period, the hottest phase of the process, where the worms won’t do any good. Instead, add your grub munchers to your compost at the beginning (mesophilic stage) and the end (maturation stage), as you’ll receive far better results.
Natural accelerators are fine for me, ranging from chicken manure, sugar water, urine, nettles, and old garden soil. But, again, practice and experimentation work best in crafting a reliable composting system that works for you and your vegetable garden.
You can also add a commercial compost accelerator, although if you do, I advise you to watch your pile’s moisture and temperature levels. For this reason, investing a few dollars in a good compost thermometer is wise to ensure your pile stays within the ideal temperature of 140°F to 160°F. Fortunately, organic options are also available.
Like to see a fabulous, step-by-step demonstration of how to work your compost to speed up the process? We’ve got you covered. The video below provides a fantastic tutorial.
How Do You Know When Compost Is Ready
Compost is ready when your pile has cooled sufficiently, having passed through all four stages of decomposition. What remains is a dark, loamy soil-like material with a texture like a sponge that feels cool. You should not be able to recognize any raw materials within. Additionally, this humus should smell earthy, fresh, and pleasantly semi-sweet.
Further, compost should initially feel moist and clump together when you squeeze a fistful in your hand, yet easily crumble when you release the pressure. As mentioned above, mature compost should smell earthy and mildly sweet. It should not smell sour, like ammonia. If it does, it is a tell-tale sign your compost needs additional time to be garden-ready. 6
If you are still unsure, perform the age-old radish test, which is an easy and practical method you can employ to know once-and-for-all if you can use your homemade humus in your vegetable garden.
First, grab a few handfuls of your compost and place about two inches within a shallow container. Next, sow a few radish seeds atop your compost, water, and provide light as you normally would. If you see three-quarters of your seeds sprout within about one week, that’s a good sign. If those sprouts continue growing for another week, you’ll know your compost is ready.
You see, unmatured compost contains phytotoxins that inhibit seeds from growing or kill new sprouts after a few days from their initial germination. Therefore, using radish seeds is an excellent test to see if your compost is mature.
Why radishes, you ask? Because radishes are prolific growers and very hardy. Their seeds also germinate incredibly fast and can grow nearly anywhere, even in sidewalk cracks. Don’t believe me? Try it. So if they can grow in your homemade compost, pat yourself on the back – your compost is done.
As you can see, several common ways exist to make adequate, nutrient-rich compost. Likewise, several factors determine how long or fast your compost matures.
The more effort and practice you put into composting, the quicker the result. Heat is an essential factor that helps decomposition when it comes to hot composting, hence the name. Regularly turning your pile and adding appropriate moisture content is necessary to keep your microbial life happy and productive.
However, cold composting is your best bet if you’re looking for a low-maintenance option. With this slower but easier method, expect your compost to be ready in 6 to 18 months or longer, depending on your climate, temperature, weather, and pile size.
Regardless of your chosen method, you can always do things to help speed decomposition. For example, you can incorporate more worms, increase the size of your compost pile to generate more insulation and heat, and even add a commercial compost accelerator into the mix to quicken the process.
Obtaining the right compost conditions comes down to your practice and experience. And that’s a good thing because, as vegetable gardeners, as much as we love to learn, we enjoy the final result of our labor and patience. So the more hands-on training you accomplish in composting, the better you’ll get and the better reward you’ll achieve in providing your plants a much-needed and appreciated nutritional boost.
Now, it’s your turn!
Which compost method have you tried that has provided the best consistent results in your vegetable garden? We’d love to know, so be sure to comment below!