Average Days To Maturity: 80-100 days
Distance Between Rows: 24 inches
Spacing Between Plants: 12 inches apart
When To Plant: Charley recommends planting Fennel in mid to late April or after last frost, but experienced gardeners can plant earlier and protect the young plants with buckets and milk jugs or start them out in a cold frame or small greenhouse. Fennel can also be planted in late summer for a fall crop. One suggestion is to plant Fennel in the spring in colder climates and in the fall for warmer climate areas. Planting in the fall in warm climates may help prevent the plant from bolting.
Planting Tip: When growing Fennel in a pot or container, make sure there is good drainage. This can be achieved by putting a layer of gravel or small rocks in before the dirt. If planting in the ground, keep the soil free of weeds and water it a bit so that it is moist when you plant.
Like Dill, Fennel grows tall so it needs to be protected from the wind. You can help make the plants sturdier by providing plenty of room for the roots to go deep. When choosing a location, consider the height and the fact that it could hinder other plant’s growth. Fennel is considered a perennial so it can self-sow, so give it room to spread if you want it to.
Preparation and Care: If the soil that you are planting in is poor, then work some compost into the soil. You can also apply an all-purpose fertilizer and work it in with the compost.
You will need to hoe or VERY shallowly till or cultivate the soil around the plants to keep the weeds under control. Be sure to keep it shallow and not damage the roots.
When the bulb gets to be the size of an egg, apply mulch to help keep it cool and to make it more tender and flavorful. This will also keep the bulb from turning green in the sun.
Make sure there is plenty of air flow around the plants to prevent rot and disease.
Watering: It is recommended that you water Fennel with drip irrigation (because they have deep roots) once or twice a week. Fennel can withstand dry conditions but if there is a drought you might irrigate a little more frequently. Doing so may help prevent bolting. The soil needs to have proper drainage but make sure that it retains enough water to stay moist and not soggy.
Water your garden (tomatoes and everything else) once a week with a 8-12 hour soaking. This will allow the soil to absorb an adequate amount of water and also limit the time you spend each week watering. If you use a sprinkler to water, do this during the day so that the plants will have some time in the evening to dry out before dark. This will limit the chances of disease. If you use a soaker hose, you can water at night. Watering with a soaker hose at night is best as it limits the amount of water lost to evaporation and keeps the plants dry which limits the chances of disease. During dry periods you may need to water more often (every 4-5 days), and watering at night is important in water conservation during droughts.
Fertilizing: Work compost and all-purpose fertilizer into the soil before planting. When the bulb begins to form add a layer of all-purpose fertilizer at half the recommended rate. Too much fertilizer will produce lots of greenery but will hinder the growth and flavor of the bulb.
Harvesting: Fennel can be harvested for its anise or liquorish flavored stalks, bulb or seeds. You can allow the plants to bloom and go to seed then cut the flowers off and hang them to dry in a paper bag. You will have to separate the seeds from a little bit of debris.
The stalks can be harvested and eaten like celery. Cut just below the junctions on the stalks. To harvest the bulb, cut at ground level just above the tap root when the bulb is 2-3 inches across. The leaves can be harvested when the plant reaches 18 inches tall or so.
Fennel leaves will keep in the refrigerator for about a week. Store the harvested seeds in a paper bag in a cool location. You can also dry the leaves and stalks and keep them in an airtight container. Freezing is also another option.
Common Insect Problems
Fennel is not bothered by many insects. If parsley caterpillars show up to dine, it is recommended that you remove them by hand.
Common Disease Problems
Fennel has few disease problems.