I have grown fennel from seed for a couple of years now. Fennel starts readily. I actually only keep a few plants. I do grow bulbing fennel because the bulbs have a nice licorice flavor and fennel slaw is great. Mostly I grow fennel because it attracts beneficial insects to the garden. It can be perennial but it only produces bulbs when young, so I replant every year.
While fennel attracts beneficial insects like parasitc wasps, hover flies, lady bugs, and lacewings. Unfortunately fennel does not like company so I plant it in a corner away from most other plants. It especially does not like to be anywhere near its' relatives, dill, parsley,coriander, or most other plants. I have fennel planted next to gingers, horseradish, and gynuura, since these plants do not appear to mind the fennel. Fennel will stunt nearly everything else around it.
I grow fennel in the ground and bulbing fennel gets to be about thirty inches tall. It can be grown in a pot, it does not need a lot of fertilizer and should not be over watered. I pot up seedlings from 4" to 6" and eventually to 5 gallon pots.
Cilantro can be grown in the cooler months and they can last up to six months with regular cutting, but they only last 6 weeks in summer. If the plants are happy they reseed like crazy, otherwise replacements have to be planted every month. I also like basil, but downy mildew is a problem and only lemon basil is thriving. Mints need to be contained and divided regularly or they either escape or choke themselves to death. Rosemary is pretty carefree if it can be kept on the dry side in the rainy season. Thyme and sage like alkaline conditions and good drainage. Lavender wants to be in the ground. Lavender needs to be cut back in January. Gingers need to be harvested after they go dormant and replanted when the new fingers sprout.