Cabbage can be winter grown in the greenhouse.

Summer is soon coming to an end. Although August and September still mean harvesting tomatoes, chilli peppers, and bell peppers, now is the time to prepare for the arrival of winter. At Spirekassen, we have been winter-growing in the greenhouse for several years. From experience, we know that a large group of plants suitable for winter cultivation belongs to the cabbage family. For this reason, we will take a closer look at cabbage and winter cultivation in this article.

The significant advantage

The major advantage of growing cabbage during the winter months is that the battle with hungry cabbage butterfly larvae is almost non-existent. Attacks from the cabbage butterfly are primarily seen in late summer if you grow cabbage in the kitchen garden. This problem is largely avoided by winter-growing cabbage in the greenhouse.

The extensive family

The family, Brassicaceae, is known as the Cruciferous family. The genus is called Brassica and consists of more than 30 species. Cabbage is naturally widespread in temperate and subtropical parts of Europe, North Africa, and Asia. All members of the cabbage family share some general characteristics.

The general characteristics are

• 4-petaled flowers that resemble a cross, hence the name "Cruciferous family."
• All members form "silicles," which are a specific type of two-valved seed capsule.
• Seeds of plants from the cabbage family are oil-rich.
• Cabbage produces chemical compounds that give them the distinctive mustard-like taste.
• Members of the cabbage family can tolerate cold and varying amounts of frost.

Members of the cabbage family can be found as a natural part of our daily food, such as broccoli, white cabbage, and savoy cabbage. We also see members in the world of flowers, such as stock, lunaria, and wildflowers like watercress. Rapeseed is grown in agriculture for oil production.

 Winter cultivation in the greenhouse

Cabbage can be winter-grown in the greenhouse and, in principle, take the place of tomatoes, cucumbers, and bell peppers when autumn arrives. It is a good idea to be well-prepared, and already in August, you should start thinking about winter. Begin by pre-sprouting the cabbage varieties that have the longest development time, such as broccoli, cauliflower, and romanesco cauliflower. Sow the seeds in August and September, so the seedlings have a good size before winter truly sets in. At Spirekassen, we usually pre-sprout them in seedling trays outdoors, covered with fleece to avoid the cabbage butterfly.

Each time you remove a tomato plant from the greenhouse, you can replace it with a pre-sprouted cabbage plant. Keep doing this until the greenhouse is completely emptied of summer crops.

The harvest is different

If you start pre-sprouting the slow-growing cabbage types in August and September, you can harvest broccoli and cauliflower in December. Don't expect large giant vegetables like in the summer kitchen garden. These vegetables are generally "mini-versions" compared to what you harvest in the summer, but their flavor is much more intense. If you sow cabbage in October, it's smart to choose cabbage varieties that develop quickly, such as pak choi and mustard greens. If the cold is intense, the plants won't grow large, but they can be eaten as baby leaf salad. Whole plants of all cabbage types are edible.

 

Potting soil and cultivation

You can reuse your soil from the summer for winter cultivation. If you have grown in self-watering containers, you can leave the planting bag and plant cabbage in it. If you have fixed beds, these can also be used for cabbage cultivation in the old soil. You can easily grow in pots and containers. Smaller pots with cultivated cabbage can be brought directly to the dinner table when it's time to harvest.

Fertilization needs in winter.

You only need to fertilize your cabbage in August and September. For the rest of the year, you should only keep the plants moist with water. If you are winter-growing in self-watering containers, you should not use the self-watering function but water the plants from above.

Types recommended by Spirekassen for winter cultivation.

We have tested the following varieties, which we find quite suitable for winter cultivation.

Vegetable cabbage	Kale
Broccoli ‘Green Calabrese’ Cauliflower ‘Flora Blanca’ Cauliflower ‘Parmac’ F1 Romanesco Cauliflower ‘Veronica’ F1 Kohlrabi ‘Delicatesse White’ White Cabbage ‘Langedijker Bewaar’ Pointed Cabbage ‘Filderkraut’ Brussels Sprouts ‘Groninger’	Kale 'Redbor'   Kale 'Westland Winter'  Senna leaf 'Golden Frills'   Senna leaf 'Purple Frills'  Senna leaf 'Red Giant'  Savoy cabbage 'Brassica Oleracea'  Garneshing kale Palm cabbage 'Nero di Toscana'  Bok Choy 'Taisal'  Tatsoi  Borecolel ’ Red Russian’