How To Make A Compost Pit, Benefits, Composting Process

Introduction on how to make a compost pit

Pit composting is also called trench composting, is less unsightly than a compost pile and less work than building a homemade compost bin. Compost is decomposed organic matter, such as animal manure and crop residues. Most of these ingredients easily found around the farm. In this article we also discuss below topics;

• Compost Making Procedure
• Advantages of compost pit
• Disadvantages of compost pit
• Pit composting duration
• What is the pit method of composting
• What are the benefits of compost pit
• What is the size of a compost pit
• Step by step process to make a compost pit 
• Compost pit dimensions

A step by step guide to on how to make a compost pit

For pit composting method, trenches or holes are dug to bury your waste. Later, you sit back and forget about it, while the organic materials gradually break down over 6 to 12 months. This method is effective for those who want their decomposing organic matter to be totally out of sight. The trench is also the best place to stick those weedy plants you have pulled up. If buried deep sufficient, the weed seeds will not see the light of day, so they won’t resprout. The trench or hole is awkward to harvest, however, so it is probably best used to enrich an area you ultimately want to plant in. This method comes at no cost but needs extra labour for digging.

Compost is important because it;

• Contains the main plant nutrients – nitrogen (N) potassium (K), and phosphorus (P) and written as NKP;
• Advances the organic matter in the soil by providing humus;
• Helps the soil hold both air and water for plants; and
• Makes micronutrients or trace elements available to plants.

Advantages of compost pit

Compost reduces greenhouse gases – When food waste goes to landfills, it cannot decay efficiently and produces greenhouse gas, methane. Composting these organic materials that have been diverted from landfills decreases the emission of methane into the environment. The huge amount of methane gas in our atmosphere is a known contributor to global warming.

Creates Nutrient Rich Soil – Composting improves the quality of soil by increasing the number of organic materials and micronutrients. Gardens and farms will thrive with the addition of compost. Some other important advantages of compost pit method are;

• Fully remove the disagreeable odour
• Simple mechanism
• Inexpensive
• Easy to manipulate
• No need for big attention
• High temperature inside the pit has killed the pathogens
• No bothersome animals are spread

Sources used to make a compost pit

Sources which can be used to pit method are;

• Agricultural waste- straw, maize waste, and dung
• Industrial waste- cardboard, paper
• Domestic waste- Eggshells, fruits, and vegetables
• Not to use- plastic, Polythene, yogurt cups, and any artificially made thing

Raw materials used for making a compost pit 

The raw materials used are mixed plant residues, animal urine, and dung, earth, wood ash, and water. All organic material wastes available on a farm, such as weeds, fallen leaves, stems, stalks, pruning’s, chaff, and fodder leftovers, are collected and stacked in a pile. Hard woody material such as pigeon-pea stalks and stubble and cotton is first spread on the farm road and crushed under vehicles such as bullock carts or tractors before being piled. Such hard materials should not exceed 10% of the total plant residues. Green materials, which are succulent and soft are allowed to wilt for 2 to 3 days to remove excess moisture before stacking; they tend to pack closely when stacked in the fresh state. The mixture of different types of organic material residues gives a more efficient decomposition. While stacking, each type of material is spread in layers around 15 cm thick until the heap is around 1.5 m high. The heap is then cut into vertical slices and about 20 to 25 kg are put under the feet of cattle in the shed as bedding for the night. The next morning, the bedding, along with the urine, urine-earth, and dung, is taken to the pits where the composting is to be done.

Location selection for compost pit making

• By making the pit close to the crop waste, you can decrease the transport cost
• Should find a hard soil because if there is loose soil, nutrients are penetrated the soil. 
• Easy to access the water
• Access to raw material

Pit preparation for making compost

Pits or trenches or about 1 meter deep are dug; the breadth and length of the trenches can vary depends on the type of material to be composted and the availability of land. The site should be selected as per the Indore method. The trenches should have sloping walls and a floor with a 90-cm slope to avoid waterlogging.

Size of the compost pit

The site of the compost pit should be at a level high enough to avoid rainwater from entering in the monsoon season; it should be near to a water source and the cattle shed. A temporary shed has constructed over it to protect the compost from heavy rainfall. The compost pit size should be about 1 m deep, 1.5 to 2 m wide, and of an appropriate length.

Points to remember when making compost in a pit

1. This is good at any time of the year where moisture is limiting and is the best way to make compost after the rains have finished and during the dry season.

2. Prepare and dig the pit, or better still, a series of 3 pits, when the land is moist and easier to dig, and/or when there is a gap between other farming activities.

3. If it is possible, make the compost immediately at the end of the rainy season while there are plenty of green and moist plant materials.

4. In the dry season, make the pit close to a place where water can be added, e.g. next to the home compound where urine and wastewater can be thrown on the compost materials, or near a water point, e.g. near a stream or a pond where animals come to drink.

5. Mark the place of the pit with a small fence or a ring of stones so people and animals do not fall into it accidentally.

How to compost in a Pit or Trench

Making a compost pit at home requires burying kitchen or soft yard waste, such as grass clippings or chopped leaves, in a simple trench or pit. After a few weeks, microorganisms and earthworms in the soil convert the organic matter into usable compost. Some gardeners use an organized trench composting system in which the trench and the planting area are alternated every other year, providing a full year for the material to break down. Others can implement an even more involved, three-part system that consists of a walking path, a trench, and a planting area with bark mulch spread on the path to prevent muddiness. The three-year cycle allows even more time for the decomposition of organic matter.

Although organized systems are effective, you can simply use a shovel or post hole digger to dig a hole with a depth of at least 8 to 12 inches (20 to 30 cm.). Place the pits according to your garden plan or create small compost pockets in random areas of your yard or garden. Fill the hole about half full with kitchen scraps and yard waste. To speed up the process of decomposition, sprinkle a handful of blood meal over the top of the waste before filling the hole with soil, then water deeply. Wait at least 6 weeks for the scraps to decompose, and then plant an ornamental plant or a vegetable plant, such as tomato, directly above the compost. For a large trench, till the compost evenly into the soil or dig it in with a pitchfork or shovel.

Indore pit method

The Indore pit method is best done during the dry season or at the end of the rainy season. It is important to make the pits where there is enough water available; for example, a small dam, by a pond, run-off from a road or track, etc. Women would not be expected to carry water for making compost. Wastewater and urine from animals and people can be collected in old containers and used in making compost.

The main reasons for making pit compost in the dry season are as follows;

1. After harvesting is complete, farmers can arrange their time to make compost including working together in groups based on their local traditions to share their labour.

2. If farmers have a biogas digester, the bio-slurry from the digester can be used to make high-quality compost at any time of the year, but particularly during the dry season.

3. The pits can be filled two or more times so that a large quantity of compost can be made throughout the dry season.

4. If pit compost is made during the rainy season or in very wet areas, water can get into the bottom of the pit. Then it will result in the materials producing a bad smell and poor-quality compost. In wet areas, it is better to make compost through the piling method.

5. Poor quality compost will not be productive and this can discourage farmers and others from trying to make better quality compost.

6. It is very important to have frequent follow-up and control of the balance of air and water in the materials being decomposed to make compost.

Covering the pit for making compost

After the pit is full of compost making materials, the top should be covered with wet mud mixed with grass and cow dung, and wide leaves such as those of banana, pumpkin or even from fig-trees, and plastic so the moisture stays inside the pit, and rain does not get into damage the decomposition process. Note: Mark the place and/or cover the top with branches so animals and people do not tread on the cover and break it. The progress in making compost should be checked regularly by taking out the ventilation or testing stick and checking it for heat, smell and moisture. The inside of the pit should be hot and moist with a good smell. The top of the pit will also sink as the composting materials get decomposed.

How to Make a Compost Pit

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Step 1) Locate a spot in your yard that collects a lot of direct sunlight to help keep your compost pit above 43°C. Do not place the compost pit too nearer to your house, as it may release an unpleasant smell as it decomposes.

Step 2) Dig the hole for your compost pit – compost hole should be about 1 ft deep. The area of the hole will be determined by the quantity of organic matter you want to add. The compost material should reach a depth of 4 inches in the pit.

Step 3) At what time of estimating the hole size, remember that the compost material will be finely chopped or torn to pieces before being thrown in the hole.

Step 4) If you have a lot of compost material with you, you can dig a deeper pit, but avoid going deeper than 3.2 feet important decomposing organisms cannot live beneath this depth. Try making your pit wider or longer if you need room for more material.

Step 5) Line the hole with masonry lining or pack in the bottom and the sides of the hole as well as you can, or you risk the sides crumbling down into your pit. Cut your compost materials finely and underground composting happens at a slower rate than aboveground setups. Exposing as much surface area of the compost materials as possible is the key to fasting the process. Kitchen scraps can be ripped apart by hand, sliced with a knife, or even pulverized in a blender or food processor. Yard scraps can be broken down by a lawnmower. Aim for pieces no bigger than 2 to 3 inches long, wide, and thick.

Step 6) Compost pit is filled with the organic materials and it is time to start composting! Dump your yard waste and food scraps into the hole, but keep in mind you do not want the materials you’ll be composting any taller than about 4 inches. Use a shovel to mix the materials so they decompose as evenly as possible. It’s especially important to make sure your carbon-rich materials (such as yard waste and paper) are mixed thoroughly with your nitrogen-rich materials (like fresh grass clippings and vegetable scraps).

Step 7) well-mixed compost materials are important from the outset, as you usually do not turn the materials as you would with other kinds of compost setups and layer the ingredients in the compost pile. Start with organic materials, such as shredded newspaper, kitchen scraps, eggshells, coffee grounds, grass clippings, or fallen leaves. Then add a layer of fertilizer, such as cow, horse, and chicken manure. And add a layer of soil in a compost pit and repeat the layers in order. Stop once your compost reaches 1 foot above the compost pit.

Step 8) Water the compost pit till the ingredients are soaked. Compost needs moisture content between 40 and 60% to multiply the beneficial microbes that are within the pile.

Step 9) Turn the ingredients in the compost pit once per week with a shovel to offer proper aeration, add water at this time to keep the pile moist. Use the compost once it becomes crumbly and brown and has an earthy smell to it.

Disadvantages of compost pit method

• Labour intensive
• Not enough practical knowledge with farmers
• Time-consuming
• Cannot be practiced in high rainfall regions
• Not enough aeration inside the pit

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