How to plant onion

Allium cepa var. strain

The onion is a biennial plant, but it is usually grown as an annual. Its bulbs are eaten raw or are prepared in a wide variety of ways, and its hollow leaves, when young, can be used as a substitute for the leaves of chives.

There are currently a large number of onion cultivars, with plants that usually reach 15 to 50 cm in height during cultivation (but can reach 1.2 m in height when they are flowering, which usually occurs only in the second year of life these plants). Its bulbs, which can vary from 2 to 15 cm in diameter, may have a white, yellow, red or purple outer skin or shell (the external cataphiles).

Onions contain substances that may have a beneficial potential for human health and are therefore also used for medicinal purposes. But while humans can consume onions without problems, they are toxic to many other mammals, such as dogs and cats.


Although the ideal temperature for growing onion is in the range of 13 ° C to 28 ° C, this is a very tolerant plant. There are many cultivars available for planting, and the onion can be grown in a wide range of regions and climates.


This plant needs at least a few hours of direct sunlight a day.

A fundamental factor in onion cultivation is to choose cultivars adapted to the photoperiod of your region, that is, the length of the day or the time of hours of light per day. Short-day onion cultivars are plants that only form a bulb when the day of light lasts 10 to 12 hours. These cultivated varieties or cultivars are suitable for places with low latitude, that is, places closer to the terrestrial equator, where the variation in the length of the day and night is not very pronounced during the year. Long-day cultivars, on the other hand, are plants that form the bulb when the duration of the day of light reaches 13 to 16 hours, being suitable for cultivation in high latitude, temperate climates.

It is possible to grow a long-day cultivar in a region and season where the days are short, but the plant will probably not form a bulb. The same occurs if a short-day cultivar is planted in places where the growing season has long days.


The soil must be well drained, fertile and rich in organic matter, but this plant is not demanding regarding the availability of nitrogen. The soil pH should be corrected, if necessary, to between 5.5 and 6.8.


Irrigate frequently so that the soil is kept moist during the growth phase of the plant. Decrease the frequency of irrigations when the bulbs are growing. Near harvest time, stop irrigation completely.


Planting can be done with seeds or with small bulbs produced especially for planting. Sowing is usually done in sowing and the transplant of seedlings to the final location occurs between 40 and 60 days after sowing. Seed germination usually occurs between one and two weeks.

The small bulbs are planted directly at the final location, at a depth of 2 or 3 cm.

The recommended spacing varies with the cultivar and the cultivation conditions, generally ranging from 25 to 45 cm between the planting lines and from 10 to 15 cm between plants.


The presence of invasive plants harms onion seedlings a lot, so they must be eliminated regularly until the plant grows completely, taking care not to cause damage to the seedlings.


The time required to harvest the onion varies widely, ranging from 85 days to almost 300 days after sowing, and depends on the cultivar used, the region where the planting is carried out and the season of the year when the onion is grown.

For immediate consumption, pull out the bulbs when necessary at any stage of development. To store the bulbs for up to a few months (usually 3 to 6 months, depending on the cultivar and the curing and storage conditions), wait until the older leaves are dry and the bulbs acquire the external color characteristic of the cultivar used. Pull the whole plant out, without the leaves coming off the bulb. Curing is the process in which the onion loses excess water. It consists of letting the onions dry in the sun for 3 to 10 days, with fewer days in hot, high-insolation regions and 10 days in high-latitude regions and less insolation. After this period, when the leaves and the outer layer of the bulbs are completely dry, the onions can be stored in cool and dry places, in braids made from the leaves themselves, tied on wooden or bamboo poles, or in crates, cutting the leaves and leaving only the bulbs. It is important for the conservation of onions to keep the bulbs dry and with good ventilation.

Related posts

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *

Botón volver arriba