Zwiebel Illustration

Onion "Rouge de Genève"

Jude Jude
29/04/2021 · 6 minutes reading time

Onions may be the most versatile and tasty vegetable that goes misunderstood for the first 15-20 years of nearly every person’s life. But then something changes. A switch flips in the cravings part of our brain, and we realise: wow, onions are one of the best veggies! You can use them in so many different ways, and they always bring something to every dish. That’s why we are excited to include this variety of onion, Rouge de Genève, in our Jack of All Trades Growable Calendar!

Here's what's ahead:

Getting Started

Here’s what you need:

  • All-purpose soil

  • Plant pots (depth min. 15 cm)

This variety of onion is called "Rouge de Genève", which literally means "Geneva Red". Is it possible that this red onion is so tasty, it is actually what inspired Switzerland to adopt a big, red flag? We aren't saying it's not true.

By the end of April, when it is time to turn the page on your Growable Calendar, you can plant onion seeds directly in your garden or on your balcony. The seeds germinate best at 15–18 °C, and they should be ready after 21-28 days.

Basic details at a glance:

  • Cover seeds with 1-2 cm soil

  • Germination temperature: 15-18 °C

  • Germination time: 21-28 days

  • Soil: All-purpose

  • Isolate: As soon as the first leaf tubes have developed after the grass-like cotyledons (only necessary if the planting distance is too small).

  • Harvest: August-September


For sowing outdoors: Tear up your seed paper into snippets and place them 5 cm apart in 1-2 cm deep grooves. If you are planning several rows, they should be 50 cm apart. You should carefully moisten the scraps of paper before you fill the grooves with soil again. Then press down on the earth carefully to keep them in place. And voilà – you’ve planted your onions!

For sowing in a pot: If you prefer to plant the seeds in a pot, make sure you allow them a depth of about 15 cm. You’ll want to take care not to soak or pack down the soil in it too much – this way you will ensure that the roots can grow deep enough. Otherwise, the same applies here: moisten the scraps of paper, cover the seeds with soil and press down lightly. The distance between the seeds in this case should be about 5 cm.


If you aren’t able to keep the planting distance to 5 cm between the individual seeds, you will have to separate the seedlings as soon as the first leaf tubes have developed – you will notice this shortly after you spot the grass-like cotyledons.

To transplant your baby onions, carefully lift out the weaker guys with a pricking stick. You can then plant them somewhere else. Poke a new planting hole for the seedlings with a pencil, plant them carefully, let some soil trickle into the hole, and then water everything.


  • Sandy-loamy soil (flower pot: all-purpose soil)

  • Loosen loamy soil and enrich it with mature compost or organic fertilizer

  • Sunny and windy

  • Neither onions nor leeks may have been grown in the same bed in the last 5 years

Good and Bad Neighbours:

Good: dill, strawberry, cucumber, carrot, kohlrabi, lettuce, tomato, zucchini

Bad: bean, pea, cabbage, radish

Zwiebeln kleingeschnitten und ganz im Glas
There aren't many bad ways to eat an onion. Try and think of one, we dare you.


  • Keep your onions moist by carefully watering them until germination

  • After they germinate, you will only want to water when the soil is dry. Onions require little water and can waterlog easily, so no need to overdo it here.

  • If the leaves begin to wither, stop watering. This means it is almost time to harvest your veggies.

  • Be sure to keep soil weed free, especially when growing outdoors, and regularly remove any buds that might form.

  • You will also want to loosen the soil around the buds from time to time.

  • You don’t need to add any fertiliser; these plants are tough guys and have pretty much everything they need!

Diseases and Pests

  • Downy mildew: Remove infested plants immediately and dispose of them in residual waste

  • Onion flies: Planting carrots as bed neighbours offers a natural protection against onion flies. You can also add crop protection nets for extra-tight security.

Harvest & Storage

  • Wait until the leaves have almost completely dried up. This means it is time to harvest your onions.

  • To gather your veggie friends, pull the bulbs out of the ground by the leaves on a sunny day when the soil is dry. The dry soil is to protect your onions, and the sunny day is for you – enjoy it!

  • Remove any remains of soil from the roots and loose skins, then leave the bulbs with their leaves on the bed for ten days. This allows the outer skin to dry and the onions will last longer.

  • You can cut off the onion greens and use them for cooking as well.

  • Remove the leaves and store the bulbs in a dry, airy and dark place, preferably in baskets or open paper bags. This way they will last until January.

  • Rotate them daily in the beginning, and be sure to keep them out of the fridge. Onions don't like cold weather. Also be sure not to store them next to potatoes, as both emit gases that interact in such a way that causes both to go bad more quickly.

Zwiebel ernte


These flavourful onions taste amazing, and they complement pretty much any dish. If you want, you can braid onions from the tubes and hang them up. Here's one of our favourite – and one of the easiest – ways to prepare these onions. We'll see how many different uses you can find for them!

Fried Onions

Step 1: Peel the onions, and using a sharp knife slice them thinly, making sure to slice as evenly as possible.

Step 2 (optional): Season your onion slices as you like. Salt and pepper are classic, but there are some other variants you can try to give your fried onions a little kick.

  • Spices! Never be shy to experiment with spices, both with onions as well as with your cooking in general! Garlic and paprika are classics, but who knows, maybe there is a curry-seasoned fried onion recipe yet to be discovered, and your kitchen could be the place for it!

  • Try soaking your onion slices in buttermilk for a half hour, then tossing them in cornstarch before frying. This will give them an extra crispiness when cooked.

Step 2: Over medium heat, prepare about 2 cm of sunflower oil in a large pot or pan. Once the oil is hot, gently drop the onion slices into the device, and allow them to fry until they begin to show some browning and crispiness. This usually takes 2-4 minutes. You will want to stir on occasion, to ensure that the onions are evenly cooked and avoid clumping.

Let us know what you think!

Leave a comment below and tell us what you think of our April plants! From the sowing to the enjoying, we want to hear from you.

Until then, have fun and happy gardening!