It depends on what type of seeds they are, Rosi. Most garden perennials would prefer to be outdoors. If they are bedding plants then they will need some warmth and protection. Did you buy the seeds in a packet - in which case see the advice on the back of the packet. If you collected the seeds from your own garden then maybe, you could put the plant name into Google and see what comes up.

I wanted to save some money and see if I was able to start plants for the summer from seeds. I purchased an aquarium w/light over the top. Brought the small bio cups that can be dropped right into the soil when ready to plant outside. Long story short, I had great success, I was able to plant an area that use to cost me $50-60 a season to it costing me the price of 3 packets of seeds at approx. $1.50 a piece.