At the moment have a 70 watt HPS lighting up three seedlings (nearly week old), its in a ventilated wooden box with temp of about 28C. Inside is covered with reflective coating, and the bulb is about 30cm from canopy.
Is it possible to have too much light, and if so do i?
the bottom of the box is 30x15 cm, so it works out at about 70w per 1/2 cubic foot.
thanks all.

Bad Lt

wow 140w /psqf!! thats almost 3 times the optimum

if the temps dont go too high (28c is fine) and you dont burn them by putting them too close to the light, all should be ok.

edit: that light would work more efficiently int a space about 30 cm x 45cm, giving 50w/psq foot

i don't really have much space to play with just yet, i used an old wine case and wired up the lighting to it with pc fans for venting. its a stop gap while i make bigger veg room for them.
Thanks for the advice.