42 watt is too low, but ya can use it in three or four days
go and buy a MH lamb and see the change.
your lamb is not enough for medium vegetation cycle of a plant
if you have good air circ. you should put the lambs to 1-2 inch, else 3-5 inch.
when you have a little light like this, your plant will be stressed and become taller, that is not a good think
146 is cool but you must reflect the fotons to the plant, for get more light. more light wont injure your plant, dont be afraid.
You can run seedlings under like 200w fluoros (a lot of people do), what the guy that the hydro store probably meant, is don't go stick your seedlings under a 600w HPS light from the get go, because that much light penetration can be bad for the plant in it's first couple weeks.