Lupin seedling development

I would put them outside, in your "blow away", on nice mild days - but beware that if it is zipped up on a sunny day they will cook :( - and then bring them in again in the evening.

pretty much however you play this the seedlings will get FAR better light outside than a windowsill (i.e. including through the plastic of the blow-away, even if it is filthy - just to use a facetious example), plus it will accustom them to being outside in readiness for being planted out, and "toughen them up".

However, I would be thoughtful about doing that with very small seedlings, but having said that I have the benefit of a conservatory so I don't have to actually make an indoor/outdoor decision daily so I'm not sure "how big" they need to be before being allowed outside for the day.

 

I'll be keeping them indoors by the look of it today, they seem happy enough at the moment.