Fennel has the botanical name Foeniculum vulgare and belongs to the umbelliferae family. Problems often arise when cultivating the tasty useful plant. In this context, two phenomena can be seen which are closely linked. The fennel shoots up and at the same time does not form any bulbs. In order to avoid this growth behavior, the causes must be investigated.
Table of Contents
variety selection
If the fennel does not develop any bulbs or only a puny bulb and shoots up far too much, then this problem may be related to the variety. In addition, this undesirable growth is particularly evident when sowing very early. It is therefore important to only use bolt-resistant varieties that form large and tasty tubers.
- Fino is a largely bolt-resistant variety
- Selma is also a fairly bolt-resistant variety
- Mammouth forms very light and large tubers and is relatively bolt resistant
- Finale is a bolt resistant strain and suitable for early cultivation
- Bianco Perfezione is a bolt-resistant variety from Italy
- sow these varieties in spring
Early sowing
If fennel is released too early, there is a risk that the plant will shoot up too quickly. In addition, early flowering in fennel is triggered by the prevailing conditions on long days. This means the days in the course of the year on which there are more than 14 hours of growth-promoting daylight. This is why the useful plant often forms no or only puny tubers if they are exposed too early in the year.
- tends to sprout flowers with increasing day length
- Growth of the tubers is then neglected
- avoid sowing these vegetables too early
- it is best to plant outdoors after the summer solstice
- after June 21st the days get shorter again
- then the growth power goes back into the tuber
temperatures
If very high temperatures prevail too quickly after germination, this circumstance also leads to an extreme growth spurt in Foeniculum vulgare . Especially as spring progresses, very hot temperatures can occur in places, which, in combination with the length of the days, promote rapid growth. This increases the stress factor in the crop, which promotes flowering. Young plants grow best when they have already developed four leaves. When the temperatures cool down noticeably in autumn and the first frosty nights set in, all the fennel bulbs must be harvested.
- prior cultivation of the young plants is optimal
- at temperatures not exceeding 16 degrees
- only then transplant into the vegetable patch
- does not tolerate strong temperature fluctuations
- can cope with slight minus degrees
- however, severe frosts lead to damage to the plant
- remove all tubers from the bed by November at the latest
planting distance
The fennel needs a lot of space to spread out at its location. If the crops grow too close together, then they are in direct competition with each other. As a result, they take each other’s light, the nutrients and water they need, so that long foliage is predominantly formed. In addition, false neighbors may secrete plant substances that suppress good development in Foeniculum vulgare. After the cultivation of the useful plant, it may only be grown in the same vegetable patch again after three years. Furthermore, a direct crop rotation with other umbellifers is not beneficial and should be avoided.
- ensure sufficient planting distance
- Plant must have at least 35 cm of space in all directions
- regularly loosen the soil during the growth phase
- Always remove emerging weeds
- ideal plant neighbors are cauliflower, peas, cucumber, radishes, lettuce and spinach
- bad plant neighbors are other umbellifers
- doesn’t like marjoram, carrots, coriander, kohlrabi and parsnips
heat & drought
If the temperature values climb steadily in summer and the soil begins to dry out, then the fennel will also not develop any or only an extremely small tuber. A layer of mulch, which is applied when planting, protects against excessive evaporation. If the sowing or planting of late varieties has been postponed for too long, the useful plant will only develop very flat and elongated tubers from August.
- Mulch soil and keep evenly moist
- water in the morning and evening when it is hot
- provide shade if there is strong sunlight
- partial shading is only possible for the tubers
