when to put under lights?

i have some white widow seedlings that are about 5" high and doing very well. i have them on the window ledge at the moment but want to put them unbder lights. I have a 400 watt HPS .
How high should the plants be before i put them on 18-6 under the light as i dont want to fry them.
Also , is there much differance in 18-6 and 24 hour light to veg. Does 24 make a lot of differance.

how many sets of leaves do your seedlings have? how long have they been growing?

24 hours of light gives your plants an extra 7.5 days of light every month. They will grow faster but sex slower, I usually grow them for a month on 24 then switch to 18/6 for a few weeks to get them to preflower before I switch to 12/12.

If they got a couple of sets of real leaves I say go for it. I would keep it at a distance of a couple of feet for a few days then start lowering it closer, unless they start to stretch in which case I would go a head & lower the light.

thanks for your replies guys. Here are two pics of the plants i have. All six are about the same size.
I have a closet grow and these are going to be tranfered to a large grow box that i have used in previous grows.

been growing for aprox 2 weeks

They are ready to be transplanted into larger pots and ready for the big light.

Fuck yea throw those girls under the real light, they look like they are strong enough to handle some HID light. Just start with your light a little further than you will normally keep it, then move it closer over the first 1 or 2 weeks.

thanks guys, they are doing well up to now. i hope they all come out fems. I used the same seeds for my last two grows and they were all females so i am hoping these will do the same ?.
I t would be nice to try a new type of seed/plant but its so hard to get them without spending lots of money. Still, white widow is a good strong smoke so i can,t complain.
I will be using the same grow set up as last time (pics attatched) It seems to work really well.

Looks good man, keep us posted

420inmyapt said:

Looks good man, keep us posted

Click to expand...

thanks man, will post again when i transplant.

plants are in the grow box and under 400HPS. will see how they get on in the next few days.

looks nice mate
just need to get a fan and lower the light abit

thanks..
I have lowered the light and have a fan and they are doing very well.
not sure if i should top them or just leave them. The last time i had 7 plants in there and got around 8 oz.