I think perhaps the lights are to stop them growing leggie.
A bit of aluminium foil is sufficient.
It is true and I use cardboard lined with foil behind the trays lined up on my windowsills later in the year. I do find the grow lights useful this early in the year though. Even with the foil backing boards, seedlings will lean to the light on the windowsills, but my house is a pretty old and the windows are not very large.
I also have a heated propagator which sits on a windowsill. Again, you can manage without, but it does give more reliable germination which I find useful, especially with some seeds, that can be expensive. I don't heat the greenhouse, so really early sowings are limited to onions, aubergines and chillies/peppers.
Perfect,
Thanks for the advice shoots. I was considering getting a heated propagator until I just checked out that link. Which would be the better investment?
If the grow lights are just for a few chillies, I would say that is a luxury. You can get by and sow a little later, especially if you are not growing the super hot ones. You might use a propagator a lot more, but bear in mind that those seedlings then need somewhere to move onto, so don't get too carried away. I've done that before believe me
Put the grow light garden on your pressie list and cross your fingers