8 Reasons Why Compost Should Be Kept Moist

Water is as important as the greens and browns in composting feedstock. Without water, decomposition will not be possible, and it is essential to check on your compost regularly and water it as and when necessary. While we know water is vital, it is crucial to understand the role of water in composting. 

So here are 8 reasons why compost should be kept moist:

  1. Moisture enables decomposition.
  2. Damp conditions help the aerobic bacteria thrive.
  3. Moisture prevents your pile from overheating/blowing over.
  4. A moist environment speeds up the decomposition of browns.
  5. Moisture prevents ant infestations.
  6. Moisture maintains the pH values of the compost.
  7. Moisture creates ideal conditions for worms and organisms.
  8. A moist environment ensures even decomposition.

Your compost is a living organism and like most living things, water is crucial for your compost pile to survive. This article will explore each of these reasons in more detail to understand why water is essential for a compost pile. This information should help you stick to a schedule of watering your compost, so read on!

1. Moisture Enables Decomposition

Compost is made when organic matter in the form of kitchen scraps, yard clippings, and other organic waste is decomposed by the activity of aerobic or anaerobic bacteria. 

Water is vital for this process of decomposition. It helps break down the organic matter by degrading it, making it easier for the bacteria to break the greens and browns into smaller pieces. Adding water to your compost pile helps maintain a steady decomposition rate.  

If your compost pile is not kept moist, the decomposition process will slow until it stagnates entirely. While it is important to remember that if your compost gets too wet, it will drown the aerobic bacteria, it is equally important to note that without water, there will be no decomposition. 

Anaerobic bacteria can continue to break down the organic matter in your compost, but without moisture, there will be no decomposition at all. 

2. Damp Conditions Help the Aerobic Bacteria Thrive

Aerobic bacteria that work to break down the organic matter in your compost pile are living organisms. Just like all living organisms, they need water to survive. These bacteria need to be watered as often as you would water plants in order to thrive.

Like plants, aerobic bacteria use water to draw the nutrients out from the greens and browns in your compost pile. Aerobic bacteria thrive when nutrients are easily available, and it is easier for these bacteria to receive nutrients from the composting feedstock and move them around.

Aerobic bacteria also need an aqueous environment to help them move around from one food source to the other in the compost pile. Moisture is also essential to provide an environment where they can reproduce easily. 

When the bacteria can move around and multiply, your compost pile heats up, and the heat encourages faster decomposition. 

Without water, the bacteria will not be able to move around or multiply easily. The bacteria will also have to do most of the work of breaking down and taking nutrients from the feedstock. These difficulties might cause the bacteria to become dormant, slowing down the composting process. 

3. Moisture Prevents Your Pile From Overheating/Blowing Over

As we’ve understood, water plays an essential role in helping the bacteria in your compost pile thrive. As the bacteria multiply, they are able to break down the organic matter faster, and the compost pile starts to heat up as a result of this accelerated decomposition. 

Temperatures in a hot compost pile can reach between 150°F to 175°F (66°C to 79°C) in the thermophilic stage, which lasts up to a couple of weeks. Most of the greens and a majority of the browns are decomposed at this time. 

However, the compost pile’s temperature can continue to increase as the bacteria multiply rapidly, reaching temperatures as high as 300°F (149°C). At this point, the pile is combustible and might even blow over

These temperatures are too high even for thermophilic bacteria to tolerate, and the bacteria will start to die off. At this stage, a regular routine of watering the compost is essential. The moisture helps bring the temperature down and ensure that the pile doesn’t overheat and kill all the decomposing organisms. 

Overheating is not only bad for the bacteria; it produces poor quality compost. If your pile overheats, then the heat can burn through the feedstock. You might see nitrogen residue in the form of white powder on your compost pile if your pile is too hot. 

This residue indicates that the heat has consumed the nitrogen instead of added to your compost, resulting in a less nutritious compost. 

4. A Moist Environment Speeds Up the Decomposition of Browns

The browns in your composting feedstock are an essential source of carbon. Browns consist of dried leaves, twigs and sticks, and other woody waste that takes a long time to break down. 

The bacteria that break down the compost need carbon for energy, but the compounds in woodier carbon sources like twigs and sticks are challenging to break down. The bacteria need to expend a lot of energy on decomposing compounds like lignin and cellulose. 

Moisture makes the work of the bacteria easier because the browns absorb the water, which then degrades the compounds so the bacteria can break them down easily. Both cellulose and lignin decompose more efficiently when the moisture levels are high.

Another factor that affects the decomposition of browns is heat because the browns in composting feedstock decompose faster in hotter environments. As we’ve understood earlier, water is crucial in helping aerobic bacteria multiply, resulting in heat generation in the compost pile. 

5. Moisture Prevents Ant Infestations

An ant infestation in your compost pile isn’t a bad thing in itself. The ants are not harmful to the composting process and may help by creating air pockets in a pile. However, too many ants in your pile can indicate an unhealthy pile. 

Ants invade areas that are undisturbed for long periods, which is only possible when your pile isn’t turned and aerated regularly. Ants like fire ants also prefer to set up their nests in loose, crumbly, cool, and dry soil. So if you see fire ants in your compost pile, it is a good indication that your compost is too dry and not heating up. 

Preventing an ant infestation is easy if you can maintain the moisture levels in your compost pile and water it ever so often, especially in the first two stages of composting. This watering will also raise the temperatures inside your compost pile to temperatures beyond what ants can handle. 

6. Moisture Maintains the pH Values of the Compost

Finished compost usually has neutral or basic pH values between 6 and 7, although these values can fluctuate between 4 to 8 during the composting phases. While the pH value dropping during the composting process is not unusual, it does release strong odors. 

When the greens in compost decompose slowly over a long time, they release organic acids that smell very strong and are usually not very pleasant. These organic acids naturally make the entire pile acidic, which then emits a more pungent odor. While the odors themselves are unpleasant, they can also attract scavengers to your compost pile. 

In most places, scavengers include rodents and raccoons, but if you live in bear country, you might find that your compost has attracted bears

Maintaining the pH value of your compost at neutral or alkaline levels reduces the odors from your pile and prevents scavengers from being attracted to it. A higher pH value indicates faster composting, which is all the more reason to keep your compost moist.

7. Moisture Creates Ideal Conditions for Worms and Organisms

Whether you’re composting with or without a bin, worms, pillbugs, fungi, and mold are all typical and expected in your composting pile. The presence of organisms in your compost is a good sign of a healthy compost that is progressing well. 

Worms, in particular, are important for composting as they do much of the work of the aerobic bacteria, helping the compost break down faster into humus. Worms breathe through their skin and require moisture levels that are much higher than that required by aerobic bacteria. 

Vermicompost bins should ideally maintain 50-70% moisture to keep the worms hydrated and keep temperatures low, so they are not killed off in the thermophilic phase. 

8. A Moist Environment Ensures Even Decomposition

Water is an essential element in ensuring even decomposition. In a compost pile, the greens are the primary source of moisture for the pile. 

These greens, like kitchen scraps or grass clippings, may clump together as they decompose, limiting the spread of moisture to a particular pocket in your compost pile. 

The even distribution of moisture also means that the bacteria can move easily across the whole pile. So rather than sticking to pockets where the greens have stuck together, the bacteria are able to work on decomposing the entire pile at once, resulting in a more even decomposition rate.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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