When is the best time to plant out??
If you're talking about bulb fennel sure that I've read somewhere that you plant out after midsummers day. If not I reckon anytime now, mine has put on a good spurt. Tried planting bulb fennel last year, maybe too early and it didn't develop the bulbs, however it's now developed side shoots with bulbs. Good luck!
We planted our bulb fennel at the end of July/ beginning of August last year and it was semi-successful. My packet said not to plant to early or it will bolt.
I planted my bulb fennel out in early July last year and was small but okay - more baby fennel than the big bulbs I was hoping for. But I think this was to do with the fact they only got about 4 hours of sunlight rather than the planting time.
I have found a better place for them this year so going to give it another go.