Thought that I would share to the world of cacti enthusiasts, what I have done to help germinate my (cacti) seed. I had been germinating cacti in a northerly facing window (in misted plastic bags, behind curtains to keep in the heat and had reletively good success.
But I decided to put an old aquarium on the window ledge instead. I lined the bottom with alfoil/tinfoil from the kitchen, and all the sides except the one facing north out the window. Put foil over the top (shiny side facing inwards) and placed the glass on top, hanging by a strip of sticky tape in the middle of the aquarium to keep in the heat. I placed the misted baggies in the aquarium and then decided to get a 25 watt light globe for added warrmth through the night.
It lookes really cheep and nasty, but it is warm as in there and after 3 days i have germinated ALL of my Astro Asterias Gonzales seeds - how awesaome is that?
Will take a photo and include it in another post if anyone is interested, but it doesn't look like much - results are another thing though.