Growing Florence Fennel

[Suzanne]

Hi..

I have only just taken an allotment on, but was hoping to grow my own Florence fennel this year. I have heard that they are very bad as companion plants and can inhibit other veg.

Has anyone got any tips on how I can overcome this.........do you have to put them in a bed on their own, or is the reputation not justified.

As you can guess I am new to this and this website, and I will be grateful for any info you can pass on.

Thanks

[Suzanne]

[Ceratonia]

The reputation is justified. Their roots secrete chemicals which inhibit the growth of root hairs on neighbouring plants and also germination of seeds. It's called allelopathy Some plants are worse affected than others by fennel (eg lettuce), but I think the general advice is to put them in a bed of their own. At least you won't have to weed so much  :)

Does anyone know how to stop Fennel from bolting? Don't transplant and don't sow too early seems to be the advice, but it bolts anyway for me  >:(

[Palustris]

The early sowings always bolt for us, butsowing in soil blocks in June and then planting out seems to work.
The bolted ones are still usable, even if they are not as pretty on the plate as the 'bulbs'.

[derbex]

I sow Alora? in June or July -in modules. If I can keep the slugs away then it's generally OK. I think that there are other, earlier varieties though.

[Jesse]

does this reputation extend to herb fennel as well?

[cleo]

umm-I`m having probs posting ??? Never had any probs with Fennel upstting other plants-I grow a variety called `Rudy` it suits my soil and seldom bolts

[Ceratonia]

It's all kinds of fennel - there is a specific chemical called Fenchone that they give off. It only has an effect on certain plants - lettuce is one and obviously the range is only as far as the roots of the fennel.

So a row of fennel next to something else is OK, but if you tried to grow lettuce between a few fennel plants, it would probably not thrive. The main effect is to stop seeds germinating.

[adrianhumph]

Hi all,  :D
                 I have grown zefa fina, for the past 2 years, sown in mid May, & later, they have never bolted & have never upset any thing else nearby (as far as i know)
                                           
                                                                Adrian.

[busy_lizzie]

Thanks for all this information.  I am going to grow Florence Fennel this year for the first time, so all this advice is very useful.  :)  busy_lizzie

[Curryandchips]

I am growing fennel - sweet florence too. The allelopathy, does this only last the one season, or does the effect remain in the soil?

[Svea]

i'll be trying fennel for the first time, after i was given seeds.
now, i understand about other plants not liking it - dill is the same as companion plants go. however, my cabbages loved the dill, and the dil;l loved the cabbages back (especially at preserving time ;D)
am i wrong in thinking that dill is similar to fennel as a companion plant, and that they should both do well among my cabbages then?

coz i sure hope so!!! otherwise there will be trouble on my tiny plot

[Ceratonia]

I am growing fennel - sweet florence too. The allelopathy, does this only last the one season, or does the effect remain in the soil?

Just while the fennel is growing. No need to worry about it for crop rotation. It's only certain things that are affected and only really a concern if you were thinking of interplanting other stuff between fennel plants. If you just have a row of fennel, next to a row of something else, doubt you'd see any problem. I was really just answering Suzanne's original question by saying that it's not just a myth - there is well understood science to go with the reputation.

Svea's example of Dill is a good one - same family as Fennel and it also secretes (different) chemicals from its root system which have been shown in scientific experiments to inhibit germination of lettuce (and many weed seeds too). Yet it did well with cabbages. There will be plenty of things that won't mind the fennel at all.

[Curryandchips]

Thank you so much Ceratonia, perhaps like many of the members, I have a thirst for knowledge, but lack the structured horticultural education, so snippets like this are really appreciated.

[Jesse]

Thanks Ceratonia :)

[Ceratonia]

I have a friend who did PhD research on allelopathy and as a result, it's the only bit of botany where I know more than I actually want to  :D

Scientific research is more aimed at finding why these chemicals work and how they affect plants (and whether they can be developed as herbicides). Farmers don't usually go in for mixing lots of different crops in a small space, so there isn't much interest in researching how dill grows with cabbage etc.

So practical experience of other gardeners is the best guide there is.

Incidentally, sunflowers have much stronger chemical weapons than fennel. Wonder if anyone has noticed any adverse effects on neighbouring plants from them?

[Palustris]

In reply to Cleo's post, we grew Fennel Rudy last year and were very disappointed, the bulbs were smaller than the ordinary ones we grew from the previous years left over seed.

[Svea]

imy cabbages loved the dill, and the dil;l loved the cabbages back (especially at preserving time ;D)

forgot to say - while the dill was alive and about to flower/flowering, they also kept the cabbage white butterfly at bay. i only had caterpillars appearing after the dill had died back.

food for thought??

[Roy Bham UK]

I didn’t have much success with Fennel last year but enjoyed the few I pulled, I’m trying Victoria F1 this year, wish me luck. ;D

[Suzanne]

Thanks for all the advice esp. Ceratonia, who I suspect is a botanist as seems very knowledgeable. I am going to try and grow it seperate from the rest of my plants for this season. And once I know what I am doing I will try to experiment.

[Columbus]

Hi all,  :)

Incidentally, sunflowers have much stronger chemical weapons than fennel. Wonder if anyone has noticed any adverse effects on neighbouring plants from them?

I haven`t noticed sunflowers holding back weed growth but cosmos have an obvious and dramatic effect. I may plant them in places to take advantage of that. I wonder of the feathery leaves that fennel and cosmos share is a clue to this property?

Col


Edit... sorry, it didn`t highlight the quote first time, I think i fixed it