sowing seeds that need cold

[peanuts]

I'm not a flower gardener, so don't know where to start with the four packets of special flower seeds I've bought that say they need cold to germinate!  Then I thought of asking on this forum, where there must be plenty of expert advice! 
I've bought some allium cristophii,  allium sphaerocephalon, campanula punctata. amd paradisea lusitanicum. 
I've kept them in the fridge in their packets for a couple of months, and I think I'm supposed to use vermiculite.  I've only used this once  before, years ago, and failed completely. 
So can anyone give me easy to follow  idiot-proof instructions, please?
Thank you!

[peanuts]

[goodlife]

It is the cold+ slight moisture that do the strafication process for seed. Sealed packets don't have any moisture in them so the seeds just stay 'in sleep'...good way to store them for long term.
When you use vermiculate...you need to wet/dampen it with boiling water to kill any fungal pathogen or any other 'nasties'..then let it cool down, then mix the seed in and pop it in fridge for the time period required by each species. I use small, lidded plastic takeaway containers that I can see through, as you need to keep eye on the seeds...any signs of possible early germination and you need to get them sown into compost without delay. Sealed plastic bags would work as well but I find in container the vermiculate keeps 'fluffier' and the seeds don't rot off as easily.
I haven't looked into those particular species exactly..but I suspect they would get enough stratification if sown in cold GH..spring is still loooong way ahead and natural temperatures should do the job.

[rugbypost]

Not a easyone to begin with, This is my way of doing it . A fairly large plant saucer about 2 inches deep mix the seeds with damp sand (not wet ) Put in the fridge for 6 to 8 weeks O/H will kill you a cold shed or your garage will do the same. After 8 weeks fill as many 3 inch pots that you think you will need with a mixture of good potting soil and vermiculite (wilkinsons do it cheap and its clean) fill the pot 3 quarter full add seed and sand mix sprinkle more soil mix over the seed very finely do not over fill and dont tamp in down to firm it in the pots. water with a fine spray bottle do not let them dry out over the next 2 to 4 weeks repot on in potting compost and plant out in july

[Digeroo]

Are you sure the alliums need such drastic treatment?  I should have thought if you kept packet in the fridge until you sow them in spring they will be fine.

[peanuts]

Thank you so much for the helpful  and very clear and explanatory replies!  i'm trying to 'go by the book' as I don't sow things like this at all, and  the allium seeds do say to sow cold, and keep them cold and damp for a couple of months, as goodlife and rugbypost have described. 
I'll probably try a few of each seeds in little  boxes in the fridge now then do a few more in a month, and a few in a pot in a cold spot in March and see what comes up.  When I can find some vermiculite in France!  I gather it isn't that easy to find, and expensive to have posted via e.g. ebay.  But I think I'll be able to track some down.  Apparently it is the same as used as insulation for a chimney insert?  Does anyone know if it exactly the same and will do the same job?

[goodlife]

Yes..it is the same stuff as for insulations...the horticultural form is just graded into smaller even size bits for ease of use.
For ordering...it is VERY light stuff..just bulky....you can achieve same by using fine sand or  sand and compost/peat mix.
You definately don't have to have vermiculate...I just prefer it for it.

[goodlife]

Oh..and to add..each of those have their preference for time scale they need of cold for good germination...so make sure you know the time...and once you expose them to warmer temp again..it needs to stay warmer(don't put into cold GH and rely weather)..being too long (or not enough) exposed to cold and afterwards having the germination temp going up and down can result no 'show' or the seedling that do come up will not grow..
..so either have to provide the right conditions or have to do some careful calculations of the average temperatures if you need to rely of the weather for the germination and after grow condition.
Oh, dear..I made it sound like science  ...what I saying, don't do too early if they have to go into cold GH after fridge...
I'm about to sow some seeds too that need stratification for 3 months...so by march the temperature in GH start to just about warm enough for germination..it may be bit erratic..but given time it should be fine..I hope that sort of explained what I was trying to say earlier on..

[Robert_Brenchley]

Use the winter weather to stratify the seed; there's no need to put it in the fridge. The freezer is too cold, though it's useful for storing rare seed. If you plant half the seeds now, and put them outside somewhere they get a bit of protection without being warmed up - in a cold frame or mini-greenhouse, or under a sheet of glass - and the rest in spring if they don't emerge, then you've got both options available. The difficult ones are things like Trillium and Paeony which are double dormant. They have to sit through two winters before they emerge.

[peanuts]

Thank you everyone.  I so appreciate all the expert advice you've given me.  Sowing flower seeds is just not my forté!  Having failed to track down vermiculite where we live in France, except via ebay with ridiculous amount for postage for a small quantity, I thknk I'll try some with fine sand as suggested, as we have that.  I'll try some in the fridge, and some outside under cover, and then some in a month or two if they don't come up.  I'll report back later in the spring!
Thank you again.