Growing onions from seeds is more complicated than planting onion sets widely. Anyone who does the work will be rewarded with small but firm tubers that are easier to store and sprout less than onion sets.
How do I grow onions from seeds?
To grow onions from seeds, you should prepare the soil in autumn and sow in spring (February to April). The seeds need a seeding depth of 1 cm, a row spacing of 20-25 cm and a germination temperature of 15-18 °C. Germination takes 3-4 weeks.
Preparation of soil and seeds
The soil for sowing onions should be loose and not freshly fertilized, as onions are weak feeders and react to overfertilization with growth problems and diseases. It is important that the beds are thoroughly cleared of weeds, otherwise the young plants will not grow. For sowing in spring, the soil should be dug up with organic fertilizer in autumn. Later fertilize with at most potash, e.g. B. with wood ash.
Seeds purchased from specialist retailers can usually be assumed to have good germination properties. If you harvest seeds yourself, it is advisable to check them for germination before sowing. To do this, the seeds are placed in a glass of water, with the he althy seeds sinking to the bottom while the “empty” seeds remain on the surface. If you want, you can use a seed bath with Humofix (€15.00 on Amazon) before sowing.
The sowing
The right time depends on the weather. Since the onions germinate at very low temperatures, they can be sown as early as February. However, the floor should be sufficiently dry. This usually occurs at the end of March and beginning of April. The onion seeds can also be grown in a greenhouse, cold frame or in a cool, bright room and later transplanted outdoors.
- Sowing depth about 1 cm
- Row spacing approx. 20-25 cm
- single to 5-10 cm depending on the variety
- Germination temperature 15-18° C
- Germination time 3-4 weeks
Tips & Tricks
Given the relatively long germination time of onions, it can be helpful to mark the rows by placing the onion seeds together with seeds that germinate quickly, such as. B. Sow lettuce or radishes. This also makes it easier to identify and remove weed competition in the beds.