If it doesn't have a drainage hole at all (not even for where a plug would go, and it probably doesn't) no. It'll get too wet and the bulbs will rot. Make holes in the bottom - I did this with a galvanized water tank from the loft with a drill bit for metal, sticking masking tape in a cross first and then drilling into the centre of that so the bit doesn't slip.

Dino161....i have an old tin bath too.you have given me an idea...I think i will wait until spring time,and maybe paint the outside of the bath too...