Growing fennel in a polytunnel

Growing fennel in a polytunnel

Fennel is another plant that has gained popularity thanks to garden greenhouses. Until recently, this vegetable was treated as a culinary curiosity, but now they can be found more often under cover. The delicate and folded fennel leaves are not only tasty, but also look fantastic. Its anise taste gives dishes a unique character, and the health values ​​are appreciated in herbal and general medicine.

This time in the Krosagro guide on crops under cover. We will tell you how to grow, cultivate and  growing fennel in a polytunnel step by step.


What is fennel?

Fennel is a perennial herb. Some varieties variety produce thickened petioles as edible parts, not the leaves themselves. Ribbed and curly stems with a greeny color contain a unique anise taste. In addition, among the varieties, you can encounter sweeter or spicier ones, so you can easily find your favorite type.

As a rule, the plants grow 3 or 4 leaves, and their upper part is decorated with yellow aromatic flowers. In the Mediterranean countries, it is planted as an element of garden design. Unfortunately, due to its thermophilic nature. It is much better to use a polytunnel for its cultivation in areas with changing weather conditions.

Growing fennel in a polytunnel

  • Positioning

The plant has high climate requirements. It needs a sunny location and protection from the wind. The optimal temperature for development oscillates between 12 ° and 18 ° C, and 20 ° to 22 ° C for germination. For growth to happen properly, it is good to keep temperatures between 15 and 20 ° C. Of course, unless you avail of a heated foil tunnel, it will be difficult to keep constant conditions. Therefore, it is worth waiting to plant under cover until a favorable environment is created.

  • Soil

The soil should quickly heat up, contain a lot of humus, be fertile and rich in calcium, and have a neutral pH of 6.6 to 7.2. A substrate with low content of macro- and micronutrients is completely unsuitable, as fennel will certainly not grow in such soil. A loamy soil, although it enables its cultivation, alters taste and development of fennel – it becomes bitter and very small.

Prepare the cultivating site in autumn if you want to plant in spring. It is important not to plant in an area where green manure was recently used. This can lead to the development of fungi that will attack it. The soil, like in the case of other vegetables, should be weeded, dug and fertilized with peat, manure and compost.

It is worth remembering not to plant fennel in the close company of dill and coriander. It can easily be pollinated by them, resulting in a lack of aroma and a different (inferior) taste.

Sowing and seedling fennel

Fennel as a plant with high climate requirements is not suitable for sowing directly into the ground. Especially in places not suitable for its development. Therefore, the seedling preparation is much more likely to succeed, with transfer to a permanent position later.

The seeds are sown in April and May in pots or multi-pots, and can enter the foil tunnel at the turn of June and July. The whole process takes about 35 days.

  • Spacing

By the end of July at the latest, the seedlings are placed in the ground with a spacing of 4 x 4. Another pattern can be implemented : 15 fennels / m2.

  • Harvesting and storage

The plant is harvested when 6 to 8 leaves have been produced. The crop can be harvested from July to November, everything depends of course on the variety. As fennel is susceptible to get damaged under low temperatures and frosts. Autumn harvest should be carried out before the first frosts. Fennel needs about three months to fully mature. It is worth taking this information into account when planning sowing to avoid weather deterioration.

If the weather was favorable and the gardener managed to obtain a developed fennel, the leaves can be harvested directly from the garden. This provides permanent access to fresh fennel, as the plant will develop new leaves. When conditions deteriorate, the bulbs are removed from the ground, cleaned and stored at a temperature of 0 ° to 2 ° C. This way, they stay fresh for up to two weeks, unfortunately losing a lot of their characteristic aroma.

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