How to make compost step by step
Making compost of good quality and without odors, recycling the vegetable remains from the garden and kitchen is something that provides great benefit for gardeners.
Some effortlessly manage to obtain good results after a short time, others, despite the effort, can only obtain a viscous and smelly paste or badly decomposed material.
In this complete composting manual we will teach you how to make compost step by step, covering all aspects so you can expect good results.
Making compost is nothing mysterious or secret, anyone who knows the basics should be able to do it.
Like all techniques, from any area of our life, the skills improve with practice. Whether cooking, gardening or horticulture, the more you practice and study, the more chances you have to be successful.
In this article
How to make compost step by step
First of all, it is important to understand the purpose of the compost you are going to make.
Where will you apply it? If you want to use it as a vegetable soil for pots, it will have to be a top quality compost.
But, if you only want to use it to incorporate into the soil or as a mulch, you don’t need such a fine result.
Second, know the key factors for a good compost.
- Amount: make as much compost as possible. The more materials there are to decompose, the better the fermentation and the less badly decomposed materials will be;
- Variety and balance: When we say to make as much as possible, we do not mean to add a large amount of the same material. Variety is a key success factor. Mix several organic materials, trying to respect the balance between carbon (“browns”) and nitrogen (“greens”);
- Humidity: Keep the compost moist. The moisture will accelerate the fermentation and decomposition of the ingredients.
Materials for composting, what to put in the composter?
Theoretically, any organic matter can be decomposed. However, some should be avoided because they attract unwanted animals, because of bad smells or because they take too long to decompose.
Here is a list of the materials you can put in the composter:
- Soft plant materials: plant scraps, kitchen scraps, grass clippings and withered flowers can be decomposed without problems;
- Woody plant materials: remnants of pruning hedges, shrubs and trees can be placed in the composter as long as they are broken into small pieces;
- Dead leaves: dead leaves fallen in autumn can be added to the composter. However, if you have a large quantity you may want to make leaf mould (or leaf mold);
- Weeds: can be decomposed and are a good source of nitrogen. Be careful not to add weed roots or seeds to the composter;
- Paper, cardboard and sawdust: they can be decomposed and work well as “brown” to balance the amount of nitrogen. Add these materials in small pieces;
- Manure: chicken manure is very rich in nitrogen and must be mixed in the composter with brown materials. Horse and cow manure, on the other hand, comes usually mixed with straw and can be added without any additional precaution;
- Straw: straw is an excellent “brown” material to add to the composter. Don’t forget to add nitrogen-rich materials to balance the amount of straw;
- Marine algae: they are an excellent source of nutrients;
- Ashes: ashes are rich in carbon but do not add in large quantities as it can alter the pH of the compost;
- Agricultural waste from the food sector: vegetable traders or restaurant owners tend to have a large amount of vegetable waste and can be a good source for your composter.
The fundamental rule is the balance between materials rich in nitrogen (green) and materials rich in carbon (brown). If you just put grass in your composter, you will get a viscous and smelly material; on the other hand, if only wood sawdust and paper are added, decomposition will not occur.
What materials should be avoided in composting?
- Weed roots: such as dandelion and grasses can survive the composting process and then be disseminated to the places where you will use the compost;
- Weeds or plants with seeds: because the seeds can later germinate where they are not desired;
- Diseased plants: it is preferable to burn them and then add the ashes to the composter;
- Plants that may contain herbicides: if, for example, you have treated grass with herbicide, do not add cuttings to the composter for obvious reasons;
- Cooked food scraps: may contain salt and fats and will attract rats;
- Dog and cat droppings: may contain harmful organisms;
- Identical materials in large quantities: as we have seen, variety is the secret, so avoid adding large quantities of the same material to the composter;
- Inorganic materials: plastics, metals, cans, glass, textiles, paints, batteries should never be added to the composter.
Shred the materials
Coarser materials, such as the remains of pruning tree branches, can take some time to decompose. The use of a shredder is advised at times of the year when there is a lot of this material to add to the composter.
By shredding the materials, you will be accelerating the decomposition process and “saving time” in the process.
Even outside the pruning season, when you have coarse materials to add to the composter, remember to break them into smaller pieces before adding to the composter.
Do I need to mix the compost?
Mixing the materials is important to obtain a homogeneous compound and to accelerate the process. Turn the materials so that the ingredients on the outermost parts of the composter are placed inside.
This will add air and cause “new” material to enter with a lot of nitrogen, ready to feed and be digested by earthworms and microorganisms.
How often to turn compost?
The frequency of turning the compost depends on several factors. The type and quantity of materials, the temperature and humidity and the progress of the decomposition (if it is in early or advanced stages).
In the beggining of the process, you can mix and turn the materials every 3 or 4 days, or at least each week. Tipically, if it is in the final stages os decomposition, it will need less turns.
Here is a good article detailing the factors that should be considered in the subject of turning the compost – by Peter Weeks.
Nitrogen-rich materials act as compost activators. Farm manure is the most commonly used material as an activator, but even human urine works as such.
If you want to decompose many woody materials, it is important that there is a lot of nitrogen available to speed up the process.
How long does composting take?
There are many factors that influence the decomposition time of materials in the composter. Temperature, humidity, the nature of the materials and their proportion, etc. In an optimal scenario, following the rules and having a good balance between the factors that influence fermentation, you can get compost ready to be used in three or four months. But it may take longer.
Consider a scenario in which you start a new composter in the spring, temperatures will rise and if you maintain a regular humidity level in the composter, the process will be quick. However, imagine that composting starts in the autumn, there will probably be excess water in the materials, but worse than that, the temperature will drop with the arrival of winter and the decomposition process will be very slow in this period.
Is the compost ready to use?
To check the progress of the compost, move the top layer away and see the state of the woodier material in the lower layers. Is it decomposed or not?
If not, it may be because it is too dry or has few green materials. Water it and add nitrogen-rich green materials.
If you already have a fluffy and crumbly material, then it is ready to be used. If the compost is to be used in pots, it may be better to sieve to remove any larger pieces. Add these removed materials back to the composter.
The composting process will naturally cause odors. But excessive smells can mean that your compost is too wet or has too many nitrogen-rich materials. To rectify this, turn the compost and add carbon-rich materials, such as wood chips, paper or cardboard. Then cover it with a layer of ready compost from another composter to smother the smells.
How to build a composter
The easiest and most immediate way to start composting is to buy a composter. There are several types for sale in garden centers and DIY stores.
However, you can build your own composter, it is cheaper and it becomes a funny project.
You can make it out of wood, with bricks or straw bales, building a square box or, as in this article, which shows how we built a fairly simple composter using poultry net.
It may also be useful to have two composters side by side, or a large composter divided in half. While one side matures, we fill the other and so we have two states of decomposition and we always have compost ready to use.
What is the best place for the composter?
The composter must be placed in a place sheltered from the sun. If the composter is open at the bottom, place it directly on the ground, facilitating the access of earthworms and microorganisms responsible for the decomposition of materials.
How to make compost pile?
If you want to simplify composting further, you can make a compost pile.
- Place a layer of coarse materials on the ground, for example tree and shrub branches;
- Add several layers of materials, maintaining a pyramidal or conical shape to help the stability of the pile;
- Cover the pile with black plastic to prevent it from drying out and becoming soaked, holding it all the way around.
This form is not so practical if you want to add materials regularly. One variation is to make a pile that grows horizontally, adding materials on one side. In this way, there is a side where you can collect compost and another side where you add materials.
The compost pile is most recommended for large amounts of material. Typically, pile composting is slower.
Are there any topics left to cover in this complete guide on how to make compost step by step? Tell us your questions or tell us your experience.