How to grow fennel organically
The organic cultivation of fennel (Foeniculum vulgare Mill.) Of the vegetable varieties is carried out for the use of its “grumolo” composed of fleshy and broad leaves. Regardless of the variety you grow (White Perfection, Sweet White of Florence, Fennel of Parma, Fennel of fracchia, Giant of Naples, Grosso of Sicily, etc.) it is important that you provide seeds or seedlings that come from organic farming.
For a good cultivation the choice of suitable land and the period is fundamental. Excessive hot or cold below 5 ° C are unfavorable to the growth of this plant. For this reason the most suitable periods are autumn and spring. The soil should be a medium mixture tending to sandy, rich in organic substance, in order to facilitate the propagation and formation of the root system.
For the autumn sowing it is also possible to start from a polystyrene seedling (it is preferable to direct sowing to avoid phytosanitary problems at the young shoot and competition with other herbs); this can take place at the end of July with transplanting in the ground in early September. For the spring sowing it is possible to sow the first of February and transplant in open field in early March. The harvest of this vegetable varies between 80 and 120 days (depending on the climatic trend). For the plant distances I recommend the one of 30 cm in the row and 60 in the rows.
Irrigation must be done according to the real needs, clearly greater for spring cultivation and theoretically less for autumn ones; in any case, irrigation must be done in order to never leave the plant with dry soil (it affects the organoleptic quality of the “grumolo” and its proper growth). The irrigation system depends on the cultivated extent. For medium and large extensions obviously the most suitable is that with hose. The stagnations must be avoided absolutely.
The fennel should be grown taking care to cover the grumolo to carry out the whitening and the greater enlargement of this. This system is carried out by periodically rearing up the plant (every 5-6 days) from the moment the grumoli start to swell up to about 15 days before harvesting. This way, among other things, avoids growth and therefore competition with other herbs. The most suitable fennel harvest time is before the flower scapes begin to form. This must be done with a spade by removing the plant from the ground and without damaging the grumolo. Then the outer leaves are removed and the upper vegetative part is cut.
Among the parasites the major annoyance is that of the black aphid (especially in spring crops); these can be removed with preventive treatments with nettle macerates (which also acts as an excellent fertilizer), garlic and tomato alternately. the
Among the mushrooms the real danger is the sclerotinia (Sclerotinia sclerotiorum) which damages the grumolo. For this phytopathology it is possible to operate in a preventive way: avoid stagnation, not too narrow distances between plants, the technique of whitening (which acts as a preventive technique) and operate an excellent rotation and association. Then follow this plant to a crop that uses a lot of organic matter or manure (such as zucchini and cucurbitaceae in general) and to associate the fennel especially with lettuce and peas.