The correct planting time and planting distance are of great importance for the sprouting of onions and the splendid growth of the plants. Here are some helpful tips for planting onions.

In a nutshell

  • Planting bulbs mostly in autumn
  • Plant onion sets from spring
  • Planting distance depending on onion size/variety
  • Missed planting time? Subsequent planting possible

Planting time for flower bulbs

Mainly winter and spring bloomers can be found among the flower bulbs. These include, for example, tulips (Tulpa) and daffodils (Narcissus). But there are also numerous summer and autumn plants that have another ideal time for planting:

  • Winter bloomers: September, November at the latest
  • Spring bloomers: Autumn before the first frost
  • Summer bloomers: between March and April
tulip bulbs

Belated planting

If spring-flowering bulbs such as tulips are not planted in autumn, they can still be planted in early spring at the latest at the beginning of March under two conditions: The bulbs must not have any shoot tips and must be relatively hard. If this is not the case, they have already invested too much energy and strength in the (too early) budding that they will lack it for further development in the soil. They either break or, with a little luck, grow the following year.

Warning: daffodil bulbs

There are different varieties of daffodils (Narcissus), among which there are early, middle and late bloomers. Early bloomers are, for example, the "February Gold" and the "slit-crowned narcissus". Here it is important that early-flowering varieties are planted in August or September so that the bulbs can form roots before the first frost. Medium and late bloomers have until November/December to plant the bulbs. Late bloomers can still be planted until the end of February, but there is the same risk as described under "Late planting".
The following are some examples of narcissus varieties as mid and late bloomers:
Blooming from March to April:

  • Large-crowned daffodil
  • Jonquilla Narcissus
  • Small-crowned daffodil
  • Trumpet Narcissus

Blooming from April to May:

  • Poet Narcissus
  • Angel Tears Daffodil
  • Tazette Narcissus
daffodil bulbs

Planting distances between flower bulbs

So that the plants do not hinder each other during their growth, it is essential to ensure the correct planting distance. Information is often provided that relates to the individual varieties. The bulb size, which can vary even with the same flower varieties, is usually not taken into account. If one flower bulb (regardless of the variety) is larger than the other, it usually develops into a more luxuriant plant, which accordingly takes up more space on the earth's surface. In addition, onions of different varieties with different onion sizes are often placed next to each other. Therefore the tip of the experts:

Planting distances between small bulbs: two and five centimeters
Planting distances between large bulbs: about eight centimeters
Tip: Early-flowering bulb plants in particular are becoming increasingly popular, with rarer specimens in particular enjoying high demand. If you want certain varieties, you should start buying/searching early or place a pre-order in summer.

planting depth

Experts have created a rule of thumb for the ideal depth for planting onions. This applies to all flower bulbs. It reads: The depth of the planting hole should be chosen so that the bulb fits three times deep and is covered with twice as much soil as it is high.
This means: if the onion is five centimeters high, a planting hole of 15 centimeters must be dug and the onion then covered with ten centimeters of soil.

Onion sets: Best planting time

As with flower bulbs, the best time to plant onion sets (Allium cepa) depends on whether they are early, mid-late or late varieties:

  • Early varieties between March and April
  • Mid-late varieties between June and July
  • Winter onions between August and October

Notice: Onion sets are sensitive to cold and do not tolerate severe frost. It is therefore advisable to start planting the bulbs at the earliest when the temperature is approximately constant at five degrees Celsius, which is usually the case in mid-March.

Onion set planting distances

Onion sets are at high risk of mildew infestation. In order to reduce this to a minimum, it is important to pay attention to the planting distances of the individual bulbs:

  • Planting distance: ten centimetres
  • Set in a row: at least 15 centimeters
  • Distance between rows: 20 to 25 centimeters

Planting depth of onion sets

Unlike flower bulbs, which should be covered with a layer of soil several centimeters long, onion sets should only be planted so far down that a third protrudes above the surface of the soil - according to widespread information. However, experienced hobby gardeners swear by the fact that harvest maturity can be reached more quickly if only the tips of the onion sets are sticking out of the ground.

frequently asked Questions

When is the best time to plant bulbs?

Plant onions are specimens that are already in the vegetation phase due to the pre-cultivation and have already formed leaf shoots. These are also placed in the bed at the times mentioned in the article, because the pre-culture “only” ensures earlier flowering or earlier harvest maturity and is recommended if, for example, autumn was missed as the ideal time. It should be noted, however, that not every onion is suitable for pre-cultivation.

What happens to the onions when it freezes?

If the bulbs have been planted on time, as described in the article, this only affects those that are planted in the ground in autumn/winter. These need the cold of winter because it stimulates flowering in spring. These specimens are protected from the icy cold by a specific mechanism by which starch is converted into sugar and freezing to death is therefore generally not possible.

Category:

Garden plants