Written by Spirekassen 27 Sep 2023 08:12

Autumn Sowing of Nigella (Love-in-the-mist) in the Greenhouse

A long summer has come to an end, and autumn has begun. Many choose to stop cultivation in the greenhouse when the winter season begins, but that is not necessary. The greenhouse can accommodate multiple seasons with different types of cultivation.

In September, it's time to sow flower seeds in the greenhouse. It may sound strange to sow when winter is just a few months away, but there is a group of flowers, which should be sown in September.


What are hardy annuals?

Hardy annuals are a specific group of summer flowers that can be sown in autumn. Their hardiness allows them to overwinter, even during longer periods of frost. Normally, hardy annuals are sown outdoors, but at Spirekassen, we have also been experimenting with sowing them in the greenhouse for several years.

In general, sowing hardy annuals is all about the timing. You need to hit the point where the plants have enough time to germinate and grow, but not become so large that they start flowering. A rule of thumb is to sow around the autumn equinox since plant growth is highly dependent on the combination of daylight hours and temperature. In 2023, the autumn equinox falls on September 23. Sowing a couple of weeks before and after the equinox usually works well. Especially in the greenhouse, you can even sow until mid-October.


Advantages of autumn sowing

Autumn sowing is the shortcut to early summer flowers. Normally, there is a small break at the end of May, where it can be challenging to find flowers for bouquets. Tulips and other spring bulbs have stopped flowering, and it takes a few weeks before the first summer flowers can be picked. With autumn sowing in the greenhouse, you will have flowers to pick as early as May, reducing the period without flowers.


About Nigella

Nigella, commonly called Love-in-the-mist, is a genus with 18 species, and the flower is an annual. It is originally native to Southern Europe, North Africa, South Asia, Southwest Asia, and the Middle East.


Easy to grow

Nigella is an elegant plant with graceful flowers and delicate foliage. It is easy to grow, as the seeds are large and easy to sow, making nigella suitable for beginners in flower cultivation.

Nigella is generally hardy, and when sown in autumn, the seedlings can tolerate the cold and frost throughout the winter without any problems. Nigella is rarely affected by pests or diseases.


Nigella loves the sun

Nigella prefers a sunny and well-drained growing location, making the greenhouse ideal for cultivation. By sowing Nigella in autumn in the greenhouse, you will have blooming Nigella plants amongst your vegetables from May. If the flowers are not picked, the plants will produce beautiful seed pods that can be dried and used in everlasting bouquets. The seeds are easily harvested and can be saved for next year's floral display.


Different varieties

Among the notable varieties is ‘Albion Black Pod’, which has white flowers with beautiful dark purple seed pods. The ‘Miss Jekyll’ series, with large semi-double flowers, is also worth mentioning. This series includes the beautiful pink variety 'Miss Jekyll Rose'.

Another species of Nigella often grown for decoration and bouquets is Nigella Papillosa, formerly known as Nigella hispanica. In this species, the plants are slightly taller, and the seed pods are different from those of Nigella damascena. Examples of the beautiful varieties of Nigella hispanica include 'Delft Blue', with wonderful flowers that almost appear partially painted with watercolours in cobalt blue on a white base. There is also the popular white variety 'African Bride', which impresses with its pure white flowers and distinct black centre.


Sowing Nigella in the greenhouse in autumn

If you don't have much experience with flower cultivation, Nigella is a good place to start. It is one of the easiest flowers to grow, and it requires minimal care throughout autumn and winter.

You can sow Nigella in the greenhouse from September. You will notice the seeds germinate, but the plants will not grow more than about 10 cm tall before growth slows down as the light decreases and the cold sets in. You may see the plants appear lifeless due to frost during winter, but don't worry. Everything is as it should be. The small Nigella plants will recover when the temperatures rise again.

Throughout autumn and winter, both the seeds and seedlings should be kept moist, but it's important not to overwater at any point. If there are prolonged periods of above-freezing temperatures during winter, water once a week. Fertilization is not necessary until spring begins in March.

There are two ways to sow and grow Nigella in the greenhouse:

Pot cultivation

You can easily reuse soil from summer pots as autumn sowing doesn't require nutrient-rich soil.

Sprinkle the seeds as you would sprinkle salt on food. Cover the seeds with a few millimetres of soil. Both the soil and seeds should be kept consistently moist during germination.

Cultivation in garden beds

In fixed garden beds, it's easiest to sow Nigella in rows. The process is almost the same. Create a trench no deeper than 1 cm and sprinkle the seeds in the trench. Cover with a few millimetres of soil and keep the soil and seeds moist.

The seeds will germinate slower than in spring. It can take between 1 to 3 weeks. If you sow around new year’s, you won't see Nigella sprouting until around March of the following year.


Supporting plant growth

Nigella plants grow taller in the greenhouse than they would outside because the greenhouse conditions are favourable for their growth. Therefore, you should provide plant support, to make sure the taller plants won’t collapse when the flowers appear. You can use a flower net, bamboo sticks, or other plant support.