Onion: planting cultivation maintenance and harvesting

Onion is widely used as condiment in the kitchen, but it is also eaten as vegetable when it is for example stuffed. All varieties of onions are appreciated, whether it is the pearl onion, or large white, red or yellow onions… To always have some on hand and take advantage of its health benefits, you might as well grow it in the garden. Here are the tips to follow for successful planting or sowing, and to meet all the needs of this condiment and vegetable from the family of Amaryllidaceae in order to benefit from an abundant harvest.

plant onions

Before planting onions, it is essential to smoke the earth which must be rich enough to promote production.

We can buy onion bulbs in specialist shops from the start of the year. They are ready to be transplanted. This facilitates the work of the gardener who is then exempted from the sowing that we will discuss in the second part, and in this way he benefits from a earlier harvest.

For a successful planting of onions, it is advisable to first dig furrows spaced about thirty centimeters apart and whose depth is limited to 1.5 cm.

People who garden with the moon will plant onions in the ascending moon, also known as the rising moon, during the Root days and harvest in the descending moon. This advice also applies to onion seedlings.

Sow your onions

Onion (garlic onion) is a plant that is grown as an annual, although in the wild it is a biennial. His edible bulb appears in the first year and must be harvested. But if left in the ground, it will develop in the second year a tall stem bearing a beautiful inflorescence white. It is this flower that provides capsules containing the seeds that can therefore be collected to sow onions on their own.

For successful sowing, you must remember this:

  • The white onion is perfect for a winter cultivation although it has a shorter shelf life than colored onions. The autumn sowing, are actually made between August 15 and September 15. They are carried out in the nursery on the fly, then the young plants are to be transplanted in place around October 15/20, that is to say when the leaves measure about 18 cm.
  • The spring sowing take place between March and May, and mainly concern the small white onions which are preserved in vinegar in order to consume them as condiments.
  • colored onions can be sown in place from the beginning of spring in all regions of France for a harvest from summer. On the other hand, it is only in the zones located in the South that they can be sown just before autumn, between mid-August and mid-September, to take advantage of its harvest the following spring.
  • Baby onions are sown in rows or broadcast in April and May, for harvest in September.

You have to sow a seed every 2 cm then cover your seedlings with only a small centimeter of soil. About 11 days after sowingthe onions begin to rise.

About ten weeks after sowing, a first thinning 5 cm then three or four weeks later, a second thinning is necessary, this time around 14 cm. The sprouts that come out of the rows can quite simply be tasted simply accompanied by a peppery white cheese or with chopped fresh herbs, or even cut into sections and incorporated into a mixed salad.

growing onions

The onion likes light soils that are not too loose, rich in manure and well drained. He hates excess humidity. It prefers to grow in a warm and sunny location. It is recommended to cultivate several varieties of onions in order to harvest throughout the year, knowing that colored onions are the only ones that can be kept all winter.


It’s not which pair temps sec we water the onions. Another key point to respect: do not water if you have to harvest in the next three or four weeks.


The colored onions need contributions nitrogen-rich fertilizer a first time at the time of thinning then a second time four weeks later. We then take advantage of a hoeing session to fertilize the land.


The onion growing space should always be impeccable. It is therefore essential to weed frequently with a hoe or by hand between the rows and at the foot of the plants. Using the hoe also allows the soil to be aerated.

Pests and diseases

The onion fly is to be feared when one does not practice rotation des cultures. It is therefore strongly recommended to grow onions only once every four years in the same area of ​​the vegetable garden. An invasion of white larvae of this parasite requires immediate destruction of all affected bulbs.

Under very good growing conditions, onions are not particularly sensitive. A excess humidity contributes to certain diseases. It is mainly the gray rot caused by Botrytis (a fungus), sclerotiniosis also called white rotor even mildew. Too acidic soil can also cause problems.

Good and bad associations

Onion can be associated in the garden with strawberries, carrots, beets, parsnips, cucumbers, lettuce and tomatoes. It should not be grown too close to peas, broad beans, beans and other legumes or even close to potatoes.

Harvest onions from the garden

It is in the spring that the white onion is harvested. Keeping for a short time, it must be consumed quickly. As for colored onions, they are harvested in dry weather, during the summer season, from July until the end of September, as soon as their leaves are dry. We equip ourselves with a fork-spade to dig up the onions with delicacy because if they are bruised they will not keep. It is advisable to let dry between 24 and 72 hours in the sun, or if it is likely to rain, sheltered under an awning or in the basement for example. They can be kept for several months in a dry room where there is a absolute darkness so that the onions do not sprout. They can be stored in wooden crates. But we can just as well suspend them. To do this, it is necessary to make boots using the braiding onionsas our elders did.

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