The egg has gone from villain to good guy countless times, but today we know that it is an excellent source of proteins In addition, it can be consumed without any harm to health, as long as in moderation. Thus, eggshells for plants, in gardening or in the vegetable garden, brings several benefits and is very rich in three minerals: calcium, potassium and magnesium, "besides being excellent in correcting soil acidity mixed with limestone," says Luciano Andrade, owner of O Especialista Serviços de Paisagismo eGardening, in São Paulo.

According to him, eggshell can be used to fertilize basically all plants, as long as it is administered with specific doses enriched with other ingredients, such as natural charcoal, castor bean cake and organic composts. "For soil that has ample space and moisture, you can apply once a month, distributing 40 grams per square meter. For potted plants, oneOnce every two months, five grams mixed in other nutrients."

Thus, the City of Recife, through the Executive Secretariat of Urban Innovation, shares a simple recipe for organic fertilizer.

Read also: Having plants at work can reduce stress

Eggshell on plants: How to make compost

You will need:

• Eggshells (four or five);
• Peel of a banana;
• Coffee grounds from a filter;
• A little water.

How to make the compost

• In a blender, beat all the ingredients until the batter reaches a paste-like consistency;
• Then apply it to the plants;
• Therefore, to use eggshells as fertilizer, it is important that they are clean and dry. It is recommended to keep them in a cool, ventilated place to preserve the nitrogen they contain.

Can I use eggshells in composting?

Composting is the process of producing compost through the biological decomposition of organic matter. It is natural, very beneficial, and can be done even by those who live in small houses or apartments.

It is possible to mix eggshells, coffee grounds, and spoiled fruit, so the mixture can be used in gardens, pots, and flower boxes.

According to the Curitiba City Hall, the best way to prepare compost in houses without backyards or apartments is the following.

Composting at home

• Compost in old plastic buckets, wooden boxes, gallon water jugs, or ice cream jars.

  Always leave the container covered to avoid bad smells and insects.

• Make the compost near a drain or place a container underneath, because it will be necessary to make holes in the container to allow the slurry, which is the liquid eliminated by the decomposing organic material, to escape.
• The liquid can either be returned to the compost mix or diluted and applied to the plants (one cup of slurry to nine liters of water).

As in any subject related to nutrition - be it of humans, animals, or plants - the secret to the success of simplicity is balance. "The only contraindication is excessive or poorly administered dosage. The main precautions are to use the eggshell always crushed and to store it in a clean, dry place to preserve its quality," warns Luciano Andrade.

Sources: Luciano Andrade, owner of O Especialista Serviços de Paisagismo e Jardinagem, in São Paulo; Recicloteca.org and the City Halls of Curitiba and Recife.