when can i use my mh bulb?

hi all what age should seedlings be before i can use my mh bulb? as i am doing a auto grow i want the best results so i dont want to use a cfl for too long. thanks

when plant is around 6 inches or so..give or take. keep it 12-15 inches away from plant tops and your good. Check with your hand though to be sure. Thats how I run my mh.

StonedBlownSkiller said:

when plant is around 6 inches or so..give or take. keep it 12-15 inches away from plant tops and your good. Check with your hand though to be sure. Thats how I run my mh.

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thanks for the info mine seedlings seem to be takeing ages there 10 days old they have a set of little leafs on then, but im just useing a 250w cfl bulb im doing the 18 hours a day, was told to maybe try 24 hours?

Id keep 18 and 6. I ran a seedling under mine from the start with light 20 inches away and after 1 week moved it down to 13 inches and its doing great. you could switch now if ya want to. heres my 400w mh seedling

i threw mine under the 400w hps as soon as i saw green poke out of the dirt. i keep them about a yard away at this point but they are doing fine and the light meter still reads stronger than the cfls that were 3 inches away. as long as they don't get so hot that they dry out constantly it should be fine. as far as 24 hr lights, i don't like it. i notice much better growth when i give them a dark period. i run 18/6 because i'm too cheap to run 20/4. plants need a rest just like people.

I put them under my MH lights as soon as they have roots but I usually start from clone. I would take a look at your roots as soon as you have a good root ball they are ready.

StonedBlownSkiller said:

View attachment 1122484Id keep 18 and 6. I ran a seedling under mine from the start with light 20 inches away and after 1 week moved it down to 13 inches and its doing great. you could switch now if ya want to. heres my 400w mh seedling

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hi there your plant looks well nice, i want to put them under my 400 but dont want none to die!!!

johndoecangrow said:

I put them under my MH lights as soon as they have roots but I usually start from clone. I would take a look at your roots as soon as you have a good root ball they are ready.

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at what age should the plant have a good root ball?