Seeds without a propagator

delski

Got a bunch of seed packets free with a garden magazine. Looked on the back of each packet today and saw that most of them say to sow in a propagator at 15-25oC temperature range and keep a polythene bag over the top. The only packet which doesn't say that is beetroot 'choggia' so I might have a chance of that germinating. Even then the beetroot says to plant direct outside in drills in March so I probably don't even need to start them off indoors.

My house will never be at 20oC (with artificial heating) and certainly not on the windowsills where I would be leaving the seeds in their pots.

Is anyone else in the same position and what do you do to get your seeds to germinate? I don't have a greenhouse nor will I spend money on heating mats etc. My windowsills and conservatory are all I have. Conservatory will be freezing unless it's sunny, so even in there the seeds will be subject to fluctuating temperatures over the next couple of months.

BobTheGardener

With a plastic bag over the top, it is surprising how warm a pot can get even with winter sunshine.  I always used to start my seeds off like that, on the inside windowsill of a south or west facing window.  As you have identified, the real issue is what to do with the seedlings after germination.  The easiest thing to do is simply wait and sow your seeds later, so that the conservatory night temperatures are more reasonable and (more importantly) there is enough daylight for the seedlings to develop properly without becoming leggy.

Loxley

I invested in a cheap growlamp last year, and it did help supplement the light coming in from the window (I positioned it so it lit the seedlings from within the room). 

Fairygirl

I do as @BobTheGardener describes. There's little point growing a lot of stuff if you can't them move them on outdoors, and it's a lot of work trying to keep them healthy when the conditions aren't ideal for them  in terms of warmth and light, or you don't have enough space. 
Completely different if you have a greenhouse, because you can move seedlings/plants into it, and also heat it [ if they require that ] until they can go outdoors. 

B3

I put mine in the porch but I noticed this year that a pipe running under the floor between the radiators on either side of the patio doors warms the floor there so I'm going to try a couple of trays there. It's North facing so I will have to move them if they try to get leggy. 
As they said above, don't sow more than you can handle. You probably don't need a dozen tomato plants and you don't want 20 lettuces maturing at the same time.
I've got away with planting cosmos in pots in a sheltered spot outside in March. As they flower late in the season, they have plenty of time to catch up.