Starting onions - heat or not?

[BarriedaleNick]

Just getting my seeds sorted for the year and am about to sow my Kelsea onions.
I have traditionaly been a set man when it comes to onions and last year I tried from seed with little success.

So this year I am going all seed and it is going to work!
To get them going would anyone reccommened a heated propagator?  I was going to do so myself but then noted that the packet says 15-20 C.  My heated propagotor gets warmer than that. Would I be better off at room temps or will the extra heat not matter too much.

[BarriedaleNick]

[Squash64]

Nick, I am by no means an expert but I started mine off in a heated propagator at
the end of December and they are doing fine. They are out of the prop. now and in
the slightly heated greenhouse.
I did the same last year and ended
up with a really good crop of onions for the first time.  I've never done any good with
growing them from sets so I'm doing seeds from now on. 

[Pescador]

I normally start mine off on a window ledge and then move to unheated mini-greenhouse once germinated. That should give you 15-20C without a propagator.

[grawrc]

I've gone crazy this year (Ok yes I know I've probably always been a bit mad! ). I sowed autumn onions in late summer, which have been out on my plot braving the elements since about mid-October, as well as planting autumn sets. I've now started off some trays of seeds on the kitchen windowsill and aim to move them to my unheated greenhouse once they're up and going. Fairly soon after germination so they don't get used to the easy indoor life! I also intend to plant some sets in March.

I've always done sets in the past but decided to give seeds a go last year. It wasn't a huge success but they didn't go out until May/June so this year I'm going for seeds in a big way and planting sets as "insurance". I never bother with propagators except for things that really won't germinate without heat. TBH I hate having the house covered with seed trays and root trainers. The cat pulls out all the tags and I haven't a clue what I planted! I'm hoping this year to transfer them to my (new) greenhouse as soon as poss.

[gavinjconway]

Heated prop to start off now. Then window sill and then cold gh in a month or so.. Once 3" high prick out and Dont overheat after that - they only need 12-15deg to grow well.. 

[galina]

Mine are just on the windowsill and after a week, I can see the first tiny seedlings.  Seems that either works, but my propagator is full with the peppers, so I had no choice 

[BarriedaleNick]

Thanks everyone - Window sill it is!  At least that leaves room for more chillis!!

[chriscross1966]

If they're in the house then very gentle or no heat is really needed.... in a GH I'd say heat until they're a couple of inches, but be tailing it off once they're up (if you have a thermostatic prop... otherwise waiti until we get a mild week forecast adn turn off the prop...once they go out onions like nitrogen early, lots adn often, but stop that by the end of may then a dose of tomato food around the end of June through mid July ....