The taproot could be about 8 inches long. Florence Fennel needs a lot of moisture and rich soil. Also once it's harvested that's it. It's not a cut and come again crop. I'm not sure (I haven't tried it) that it would be a good candidate for pot culture.

Since you've posted in the Herb rather than the Vegetable forum is it actually Florence fennel you want to grow?

Thanks! I had never tasted fennel at all, but had some back in the summer, cut up and sliced into a salad. Really good! I'm planting an herb garden this spring, guess I just jumped from herbs for adding to salad, to fennel! I know it's not really an herb! I was worried the tap root would be too long for my herb bed, but with your info about the tap root, I think I'll try it there. The bed is about 10 inches deep so should work OK. Thanks for your help!

You'll need several plants as once you've harvested the bulb that's the end of it. Good luck.

Florence fennel (Foeniculum vulgare var. azoricum) is both a vegetable, an herb and a spice! The feathery fronds are used fresh in salads and to flavor fish and soups and have a dill-like flavor. And the dried seeds are common in various recipes and in cuisines from around the globe. And the bulb can be eaten both cooked and raw and has a distinctly anise or licorice flavor, although that fades with cooking.

This link may be helpful.

btw, if your bed has no solid bottom - assuming your herb bed is a raised bed - then there is little to worry about. Even though the bed is only 10" deep, provided there is soil below the enriched soil filling the bed, the root will extend down into that soil as deep as it needs to grow.

All that is absolutely true but I was trying to make the point to the OP that if you've harvested the bulb it will not regrow and there will be no further leaves or seed in the future. On the other hand, the straight herb fennel will go on for years.

It probably depends on your climate as to how successful you'd be.

I have some Florence fennel growing in pots about 60 cm tall. But it's really difficult to get a decent bulb on them in pots, at least in my climate. Once it gets hot, they bolt and the bulb won't get any bigger. They need watering very frequently, too.

The ones I want the bulbs from, I grow them in the ground. The ones in pots I grow for other reasons. But if I were intending on harvesting the bulbs from the potted plants, I would sow them in late winter or early autumn, rather than spring. Because they always bolt by late spring where I am.

Dill roots go to a similar depth, and I also grow them in pots. But it's the same story: when it gets hot, they're way more likely to bolt growing in a pot. And with Florence fennel, that means you won't have enough time to get a good bulb.

Thanks, Sophie! I'm further north, Zone 8b, but I think I'll wait until next fall to plant the fennel. I love the taste of the bulbs, and it seems hard to find them here, but I think I'll have better luck if I wait!

Okay, so your winters are probably not much colder than mine. I reckon sowing at the early fall would give you the best success rate. There's nothing stopping you trying out a spring planting if you want, though. Even if they end up bolting before you get a good bulb, the leaves are super tasty and they attract a lot of ladybugs.

One other, unsolicited bit of information. Just in case you're not aware. If you end up growing it in a bed, or anywhere in the ground, just be careful with what you grow it next to. Fennel is supposedly an allelopath, so I tend to grow it on its own.

Thanks! I'm going to grow it in a large pot, and might try it now just to see what happens! BTW, your "I reckon" struck a chord with me! My family is from north Alabama and Tennessee. Sure good to hear someone say "I reckon" again!

Hehe! Southern expression I guess, although I'm much deeper south than the Deep South ;)

Best of luck with it!

It's common in UK English. Maybe Sophie inherited it from the Poms.

Probably, floral: my parents are English migrants. Plus it's very common in Aussie English too.