Guide to start composting at home

Let’s define it, then: composting is a biologic process in which microorganisms transform food and garden scraps into a natural fertiliser. In other words, if we let organic waste rot carefully, it will decay and decompose, originating a natural, nutrient-rich fertiliser. This process contributes to improving the soil – both at nutritional and structural levels –, increasing plant endurance, reducing the resurgence and spread of diseases and vermin, and to avoiding the use of chemical fertilisers.

Making use of that natural fertiliser will certainly grant you the best garden of the neighbourhood.

The compost – technically designated as humus – that results from this organic waste transformation can be produced by two processes (get ready for somewhat pompous, but not complex terms):

• The biological process itself

  That is, by the action of microorganisms that help the residues break apart. This process is slower than the next one;

• The vermicomposting (“vermi” as in worms)

  This process uses the precious help of earthworms to speed up the process. These lovely friends eat daily the equivalent of their weight (or more!) in organic matter, which just makes everything much faster. It is considered a very good option for those who don’t have a lot of outdoor space or live in a flat.

Although the process is quite easy, there are some things to be careful about.

The waste to be composted are divided into two categories: the greens – generally moister and nitrogen-rich – and the browns – dry and carbon-rich.

But there are as well residues that should not be placed in the compost bin. Food leftovers with meat, fish, bones and dairy must never be included in a compost bin, since they cause bad smell and attract pests (mice, rats, cockroaches, and several other insects) or even bigger animals like dogs, cats, and birds.

These are the three main “ingredients” you need to get successful composting, and all three must be in the right measure.

As such, your compost bin must be well aired and never compressed, the residues must be moist but not wet, and the temperature must be high but not too high (specially if you’re going with vermicomposting, as too high temperatures might kill the worms).

Now that you are informed, get to work, and create your own compost bin! Give your organic waste a better destiny, and that big pile of dry leaves an actual purpose.

1. Choose your compost bin

   You can find compost bins in most Garden & DIY shops. These can be either plastic with perforations on the bottom, or even wooden with a lid and no bottom. Alternatively, you can also build a compost bin yourself with pallets, for example. In case you opt for vermicomposting, the compost bin does not need to be in contact with the soil or even perforated.

2. Choose the right place

   Look for the perfect spot to place your compost bin. Choose a spot that’s sheltered from direct sunlight and rain. It must, however, be well aired.

3. Pay attention to airing and draining

   Lay some small tree and bush branches at the bottom of your compost bin – without compressing them. This first layer will allow the air to flow and the draining of excessive moisture. You can even use a bottomless bin to allow the residues to be in contact with the soil and, thus, facilitating the draining.

4. Layered residues

   Layer your residues starting with a layer of “browns”. The layers must be, depending on the size of your bin, between 5 and 10 cm thick. Do not compress the residues inside the bin.

5. Watch out for the moisture and temperature

   If you notice your composting is too dry, add some moisture by lightly watering it. If, on the other hand, you notice it becoming too wet, add more dry leaves and other browns. Measure the temperature periodically to make sure it is high. Use a pitchfork to turn your composting pile over every 7 to 10 days.

After around six months of composting – depending on the residues you put in your bin and on the method you chose – your pile must have been all broken down to compost. This humus looks like soil, smells like wet soil, is non-toxic and, more importantly, is filled with nutrients which are very important to the soil. In the case of vermicomposting, the whole process will take about two weeks.

You can use the compost as fertiliser to your garden or vegetable patch, or even to add to potted plants. Do you know that mini herb garden? Compost is great for oregano, basil, mint and even for cherry tomatoes!

In a vegetable garden, you should use 2 to 3 kg of compost per sqm. In pots, you should use 1/3 of compost per 2/3 of soil. When using the vermicomposting process, the compost is more concentrated, so you should reduce its quantity. It is possible as well to seize the liquid that forms in certain compost bins, in the proportion of 1/10 of liquid for the remaining water.

Besides the clear benefits for your plants and trees, composting helps decrease the amount of organic residues sent to landfills or to incineration plants, as well as the use of chemical fertilisers. It is a natural process that makes it possible to close the cycle and transform your residues back to soil – where life started.

Oops! My composting has an unpleasant smell! What do I do?

If the conditions of temperature, moisture and airflow inside your bin are ideal, your composting pile should not have an unpleasant smell, like the smell of “rotten”. This smell is produced when there are too many green residues, when the layers are too compressed, when airflow is blocked, or even when the pile is too moist.

In any case, just add more browns – dry leaves and straw, for example – and give it a good turn over with a pitchfork.

Oops! My composting is not in the right temperature range! What do I do?

If the temperature inside your compost bin is too high, that means it lacks greens or it has insufficient draining or airflow. Turn the pile over regularly and add some greens.

If, on the contrary, the temperature is too low, it means your compost bin needs either more residues and layers, or more airflow.

Oops! The process of composting is too slow! What do I do?

Check if the materials are small enough (20/25 cm) and add a bit of soil to activate the process.

Not having all the conditions to compost is not a synonymous of waste. You can “donate” your organic residues through the platform ShareWaste, in which you can register and signal your availability to donate or receive organic residues. Several municipalities have also communitarian compost projects that you can use (check with yours).