Seedlings under HPS 600

A question from a fellow grower:

How old do my seedlings have to be before I use a 600 hps tent 1.8 height 1.2 width with a five inch out take I think my tent is to small please help

Sorry 1.8 feet and 1.2 feet wide ? if that’s so your light might be to much for space - height of grow space ?

You say 1.8 height, this is meters correct. Like close to 6 feet, and then 1.2 meter Square? or 3 1/2 feet.

If I were you I would go to a 300 watt 60 watts used with 2600 lumes florescent light. I used one for some time even in veg. But I would not go more than 400 watt hps in such a small space
Hope this helps