Growing onions: is it better to sow seeds or plant bulbs?

Onions (Allium cepa) are easy to grow. It grows everywhere in France. There are several options for planting it in the vegetable garden: from bulbils or from seedlings (seeds).Let's see what these two techniques consist of and which one is right for you.

Sowing onion seeds in the vegetable garden

Growing onions from seed offers the great advantage of a wide choice of cultivars or varieties. The downside is that it can take up to four months for your crop to reach maturity. Gardeners who live in regions with cold winters will therefore need to start their onion seedlings indoors before transplanting outdoors.
Before buying, always check a variety's requirements in terms of light or recommended latitudes.

When to sow onions in the garden

Onions like cool weather at the start of their growth, so they should be planted from February to April, frost-free, except in regions with mild winters, where onions can already be planted in autumn. As a general rule, onions produce tops in cool weather and form bulbs when the weather warms up.

If you're sowing indoors

Sow onion seeds four to six weeks before the last average frost - or even earlier indoors or in a cold frame. When indoor seedlings have reached a height of a few centimetres, harden them off by exposing them to night-time temperatures above freezing.

If you sow them outside

Outdoors, sow the seeds in thick rows about 1.5 cm deep. You can try mixing in radish seeds both to mark the rows planted and as traps to attract root maggots away from the onions. More tips for planting onions in the garden in this video.

Planting onion bulbils in the garden

Bulbils are immature bulbs grown the previous year and offer the most limited choice of cultivars. Their advantages: they are the easiest to plant, the earliest to harvest and the least susceptible to disease.

If you plant bulbous onions, they can be identified as white, red or yellow rather than by the name of the variety. They should be planted in winter, between February and April. More information on planting dates can be found here. If you're looking for more information on the technique for planting bulbils, it's similar to that for ai, to which we've already devoted a nice article. Find out more here.

Watering onions

Onions do not like excess humidity. In wetter regions such as northern France, we like to plant it at the top of a small mound so the water doesn't stagnate around the bulbils, which could rot. However, this doesn't mean you should leave the onion without water during periods of drought. The easiest technique: open a small trench between the rows and fill it with water. This feeds the roots, while leaving most of the soil surface dry.