Transforming kitchen and garden scraps into top-quality compost is easier than it seems and incredibly beneficial for your plants. With home composting, you're doing your part to help the environment. circular economyYou reduce waste and achieve a more spongy and fertile soil without resorting to chemicals.
Beyond being a fad, home composting is a practice with thousands of years of history that is now making a strong comeback due to its environmental and economic value. By learning to compost, you transform waste into a resource: you obtain a nutrient-rich material that improves substrate structureIt increases water retention and promotes soil life, also helping to prevent pests.
What is composting and why do it at home?
Composting is a biological process in which bacteria, fungi, and small invertebrates (including the earthworms, watch domestic vermicompostingThey decompose organic waste under controlled air and humidity conditions. The result is compost: a natural and stabilized fertilizer which enriches the soil and makes it more resilient.
Making your own compost reduces the organic fraction that ends up in landfills or incinerators, preventing polluting emissions and helping the environment. fight against climate changeAt home, it also means savings: you reuse what you used to throw away and you do without commercial fertilizers.
Compost provides nutrients (N, P, K and micronutrients), promotes soil particle aggregation, improves infiltration and reduces the erosionIts main uses include fertilizing pots and gardens, restoring degraded soils, and, on a large scale, even generating [something]. biogas in specific facilities.
Green and brown materials: the balance that makes the difference
For the process to go smoothly, you need to combine two groups of materials. These are called green (rich in nitrogen) activate microbial life and accelerate decomposition. brown (rich in carbon) provide structure, prevent caking and help control moisture.
Among the greens, you can add leftover raw fruits and vegetables, coffee grounds, and tea bagsfreshly cut grass, tender leaves, withered flowers and crushed egg shellsThey are moist materials that decompose relatively quickly.
Browns include dry leaves, straw and hay, small twigs and chips, cardboard and paper without lamination or problematic inks, sawdust from untreated wood, nut shells, and even corksDry and fibrous, they keep the compost aerated.
As a rule of thumb, aim for a ratio of 2-3 parts brown to 1 part greenIn practice, this translates into slightly thicker brown layers than green ones, or adding a good "handful" of extra dry material each time you add fresh material.
What goes in the compost and what doesn't
There are materials that should be avoided to keep the process clean. without bad smells Nor should pests. They shouldn't be in your compost bin. meat, fish, bones, or dairy productsoils or grease, pet excrement, treated wood, paints or chemicals, diseased plants, or weeds with mature seeds.
On the other hand, fruit and vegetable scraps, coffee and tea grounds, eggshells, dried leaves, pruning clippings, untreated sawdust, used napkins and kitchen paper (in small quantities), torn cardboard, and thin twigsYou'll see that some guides mention fish bones or other animal remains; technically they compost, but at home it's best to leave them out to avoid unwanted animals.
A useful note: although pet waste is not added to home composting, there are natural fertilizers such as bat guano These have been treated for agricultural use and have high nutritional value. They are not mixed in home composters, but it's good to know they exist.
The 4 phases of the process: this is how your stack evolves
Transforming your waste into “black gold” It goes through stages with different temperatures and microbial activity. Understanding these stages helps to adjust aeration and humidity at each stage and to understand why the pile heats up or cools down.
Phase mesophilic (2-3 days): At moderate temperatures, mesophilic microorganisms begin the decomposition of simpler compounds. The pile becomes "activated" and begins to generate heat.
Phase thermophilic (1-2 weeks): At temperatures above 45-60 °C, thermophilic microbes break down complex molecules such as proteins and fats. This stage sanitizes the material and accelerates the process, improving the quality of the final compost.
Phase of cooling (weeks or months): the temperature decreases, the rate of decomposition slows down, and organisms that work more slowly appear. This is a period of consolidation of the mixture.
Phase of maturity (months): Microorganisms act slowly on the most resistant waste until it stabilizes. Depending on the climate, materials, and handling, this can take several months or even approach a year in very cold and infrequently turned piles.
Step by step: setting up your compost bin at home
The first move to set up your compost bin at home It's about choosing the right place. Look for partial shade and good ventilation to prevent the contents from drying out too much or becoming waterlogged. A patio, a corner of the garden, or even a balcony will work if the container is well-designed.
A commercial composter with a lid will work, or you can make one yourself from pallets or a sturdy fruit crate. It's important that it allows air to circulate and retains moisture. If possible, place it in contact with the ground to facilitate the entry of earthworms and beneficial microorganisms.
Before adding waste, place a metal mesh (avoid intruders such as rodents) and spread a 2-3 cm layer of fine soil. On top of that, start alternating layers: first brown material (twigs, dry leaves), then green (kitchen scraps), and so on.
Maintain a 2-3:1 ratio in favor of brown. Cover each layer with a dry layer to seal in odors and little fliesAfter each batch, spray water if the area is dry: the ideal humidity is like that of a well-wrung spongenever dripping.
Avoid compacting too much. Loosen with a fork or stick. every 7-14 days To add oxygen, and if you notice the pile becoming compacted or smelling strange, aerate it more frequently. If it's excessively damp, add more brown material; if it's dry, add water sparingly.
Humidity control and ventilation: the heart of success
Without water and oxygen there is no aerobic composting: the process slows down or becomes anaerobic and pests appear bad smellsCheck the moisture by hand a couple of times a week; add water if the material crumbles when dry, and compensate for the excess with leaves and shredded cardboard when you see it dripping.
Ventilation is equally important. Turning it over is not the same as hitting it over. Move material from the edges to the centerwhere higher temperatures are reached, and loosens compacted layers that stick together. A turning schedule of 7-10 days usually works, although in cold climates you can space it out to 2 weeks.
The temperature will tell you how things are going: if the core is warm or hot to the touch, decomposition is progressing. If it never gets warm, check the ratio of greens and browns and the humidity, there is probably a lack of nitrogen, water or oxygen.
Maturation time and signs that it is ready
The schedule depends on your management practices and the weather. With chopped materials, good mixing, frequent aeration, and adjusted moisture, you can achieve usable compost in [timeframe missing]. 2-6 monthsIf you leave it "on its own" and in cold conditions, it could take 6-12 months.
When compost is mature, you can barely distinguish the original materials. dark brown colorIt should have a loose texture and a pleasant, earthy forest smell. It shouldn't smell fermented or like garbage. If it smells bad, it's either not well-ventilated or too humid.
In tall containers, the material at the bottom is usually ready before the material at the top. You can open it from the bottom (if your composter allows it) and harvest only that fraction, letting the rest continue its process above.
Common mistakes and how to avoid them
Strong odors: These are usually due to waterlogging, lack of air, or too much greenery. Solution: Aerate the pot, add dry brown material (leaves, cardboard), and check that the top layer is finished with dry layer.
Slow growth: usually lacks nitrogen, heat, or chopping. Add more greens, water if dry. It's better if the remains are chopped up. and increases the turning frequency to raise the temperature.
Pests or unwanted visitors: these are reduced by avoiding animal products and sealing the composter tightly with a lid. Always adding a final brown layer (leaves, cardboard) helps to conceal the fresh remains no longer attracts insects.
Compost too wet: correct with plenty of absorbent brown material (straw, leaves, cardboard) and opening the container to ventilateAvoid watering out of habit; first check the actual moisture with your hand.
How to use compost in vegetable gardens, flower gardens and flower pots
To prepare the soil before sowing, add 2 to 5 cm of compost on top of the soil and mix it in. first 10-15 cmIn pots, combine approximately 1 part compost to 3 parts substrate to enrich without saturating (see homemade fertilizer for potted plants).
As mulch, spread 2-5 cm around your plants to retain moisture and protect the soil, leaving the base of the stem exposed to prevent fungal growth. In established crops, a surface application followed by watering will revive vigor without the need for chemical fertilizers (see homemade fertilizers for your plants).
If you like to be extremely precise, you can prepare a "compost tea" for watering or foliar spraying. It's a liquid extract loaded with beneficial microorganisms which complements the solid fertilizer.
How to make compost tea step by step
Use chlorine-free water to avoid damaging the microbiology: ideally rain waterdistilled or tap water left to stand for 24 hours. Place 1 part mature compost inside a cloth bag and submerge it in 10 parts water, obtaining a liquid manure.
Let it sit for 24-48 hours, stirring occasionally. Then, use the liquid within the next few hours to water the base of the plants or spray the leaves. If you can't apply it immediately, store it in a cool place and Shake it before using.
Practical tips for sustainable composting
Alternate layers of wet and dry waste, maintaining a 2-3:1 ratio and always finishing with a brown layer. This structured "sandwich" minimizes odors and insects and keeps the circulating oxygen.
Use a composter with a lid to stabilize temperature and humidity. Ventilate with a weekly or bi-weekly turnoverespecially on warm days or if you detect a sour smell, which indicates a lack of ventilation.
Water only when the surface and middle layers are dry. The goal is that "wrung-out sponge" type of moisture. If you see a grayish tint in the inner layers, it's usually a sign of... excessive drynessAdd water.
Remember that the base with metal mesh and soil helps with drainage and inoculation of microorganisms. Cutting things into smaller pieces speeds things up: thin branches, torn cardboard, and chopped kitchen scraps. they go before.
When the bottom part is ready (dark, loose, and smelling earthy), remove it and let the rest run. This way you get compost without slowing down the process. transformation cycle from the upper layers.
Environmental note: real impact on waste and climate
Up to 40% of household waste can be organic and compostable. By treating it at home, you prevent it from ending up in landfills where it generates methane, a greenhouse gas with a much higher warming potential than CO₂ (estimated at around 20 times more powerful (in certain timeframes). Every bucket of waste you turn into compost reduces your ecological footprint.
Furthermore, the use of compost as a soil amendment reduces dependence on synthetic fertilizers, decreases erosion, improves water retention, and promotes soil biodiversityIn farms and municipalities, its implementation cuts waste management costs and helps to regenerate degraded land.
Composting at home combines tradition and the future: you reduce waste, nourish the soil, and care for your plants with natural fertilizer, balancing green and brown materials, controlling moisture and oxygen, and respecting maturation times. With a few simple habits (covering, turning, alternating layers, and watering only when necessary), the process is clean and efficient, and the result is a... invaluable resource for urban gardens, flower gardens and flower pots.
