[Benandbill]

On my packet of carrot seeds, it says the months I Can sow are March til July.  August to November are the months the packet says you can harvest.  I'm planning to grow them in between rows of onions to try and deter the carrot fly, but I need to know when to plant the onion sets so they're already shooting before putting the carrots in, and also, not to put the carrots in too late in case the onions are gone... When do carrot flies stop laying eggs?

It's a bit early to put onion sets in here at the moment I think as it's still quite frosty in the mornings?

I don't ask much do I   

[DD.]

Although obviously promoting their own product, this is worth a read:

http://www.gardening-naturally.com/acatalog/Cabbage_root_fly_and_carrot_fly_control.html

There is anecdotal evidence to suggest that the carrot fly does not go out of season in the current climate. It's is generally recommended that you sow early (Feb/March) or late (June onwards) to miss them. In my book the first sowing is a bit too early to ensure good germination.

As regards companion planting, I'm not at all convinced. My plot neighour grew onions between his carrots a few years ago and they were riddled with them. The ones under my Enviromesh were not touched in the slightest.

If you do want to try, though, I'd suggest popping your onions in soon, they'll stand a bit of overnight cold, whereas they wouldn't be too keen on a proplonged spell.

[plopleuk]

Claire from the new horticultural show and youtube grows them with onions see here
http://www.youtube.com/user/clairesallotment#p/u/122/cRwLre5rU5Y
but i am not convinced so will be protecting with enviromesh.

[DD.]

As I've said, I've personally seen failures, so I'm sticking with the mesh.