How close is too close

[stully]

I just purchased an HPS 400 watt system. I I have a small seedling, that I have been giving fluro for the first week and a half of its life I want crazy buds, but I don't want to burn the seedling up. My understanding is the light should be 18-24 inches from the top of the plant. But due to the fact that this is a new light for the plant, i don't want to introduce an extra 47K lumens(not to mention the heat)very aggresively. My plan is to put the light about 4 foot from the seedling and slowly as the plant gets stronger I will move closer. Or should I just go for it and bathe the plant in light??

 

[Ms.Fox]

Start out at 24". Put your hand down to where your seedling is. Let the light hit the top of your hand for 2 minutes. If your hand starts to get "too" hot then you know you need to raise the light up more. If you notice your seedlings stretching in the next day or two, then you know your light is too far away. Make sure you have adequate ventilation.

 

[stully]

Start out at 24". Put your hand down to where your seedling is. Let the light hit the top of your hand for 2 minutes. If your hand starts to get "too" hot then you know you need to raise the light up more. If you notice your seedlings stretching in the next day or two, then you know your light is too far away. Make sure you have adequate ventilation.

hey thanks alot when you say adequate, what would be considerd adequate. I got a double door closet with one door open and a window fan(double) blowing in at soil level. Do I have to put a fan on the light itself?

 

[Ms.Fox]

That sounds good. You have a thermometer in there to monitor temps? It's always a good idea to ventilate the light. ;-)

 

[stully]

thank you

 

[stully]

I do have a therm the temp b4 the new light was normally aroung 77-78 the temp after the light has already jumped to about 80. The closet is in the laundry room and the temp in there is about the same.