Cannabis.com



View Poll Results: Is a 400w MH 36" from my seedlings okay?

Voters
7. You may not vote on this poll
  • Too High

    3 42.86%
  • Just Right

    4 57.14%
  • Too Low

    0 0%
Results 1 to 9 of 9

Thread: Light distance for seedlings

  1. #1
    asintx's Avatar
    asintx is offline Registered+
    Join Date
    Apr-07-2006
    Posts
    116

    Light distance for seedlings

    I have some seedlings just up, and have them under a 400w MH 36" above them. I'm concerned about stretching, a problem I have had with unsuccessful grows in the past. Is 36" too high, too low, or just right? I know I will need to lower the light once they are vegging sufficiently.

    I have read various posts in searches and the distances discussed range from 2 feet to 4 feet, so I am not sure what to do.
    ASINTX

  2. Cannabis Seeds | Cannabis Seeds



    Cannabis Seeds Delivered World Wide, Top Free Seeds with ALL orders. 

     

    Medical Marijuana Dispensary Finder

    Medical Marijuana Directory


  3. #2
    latewood's Avatar
    latewood is offline Banned
    Join Date
    Jan-11-2005
    Posts
    4,103
    If you see stretching, you can lower light as close as your fans will allow you.

    You need a fan solely to blow between the lamp and the canopy. Add an oscillting fan to move air around. With a fan blowing right between the plants and canopy place your hand right above the seedlings...lower your lamp 6" at a time until your hand gets hot! Move lamp up 2-3 inches and test again. If you can have your hand on the top of your canopy for a minute, withyout feeling HOT heat, then the light is NOT too close and won't burn your plants; However, you must monitor this height daily to keep from burning your tops. hope this helps. lw

  4. #3
    asintx's Avatar
    asintx is offline Registered+
    Join Date
    Apr-07-2006
    Posts
    116
    Thanks, Latewood, for the excellent information!
    ASINTX

  5. #4
    latewood's Avatar
    latewood is offline Banned
    Join Date
    Jan-11-2005
    Posts
    4,103
    I would like to add, A little stretching is not always a bad thing. I have found that If I want to grow plants lower in stature. then by stretching them a little, you allow more light penetration to the lower budsights. This is a matter of opinion, but I have a 400w MH for seedling/clone veg.
    How deep, south, asintx? Tx?

  6. #5
    asintx's Avatar
    asintx is offline Registered+
    Join Date
    Apr-07-2006
    Posts
    116
    Yup, south TX.

  7. #6
    latewood's Avatar
    latewood is offline Banned
    Join Date
    Jan-11-2005
    Posts
    4,103
    I grew up in San Angelo...

  8. #7
    krustythfreakinclown is offline Registered+
    Join Date
    Apr-16-2006
    Posts
    358
    You are wasting perfectly good money on electricity to power a light you don't need.

    If you get a couple of CFL's, electric cords and cheap reflectors from Home Depot or Lowes, you'll save a TON on electricity.

    Remember, CFL's can get as close as 2 inches from seedlings and you only need 20-50 watts/sqaure foot. And, they burn cooler, and cost less for more light output.

    Good luck!

  9. #8
    latewood's Avatar
    latewood is offline Banned
    Join Date
    Jan-11-2005
    Posts
    4,103
    although you can have fun and even grow some nice plants using cfl's...you will never achieve the same results as a 400w HID.

    don't kid yourself...If you are not limited by grow room size or heat, due to poor circulation...Then you need to use HID's.

    I have used cfl's and they do nicely for veg, but do not match any of my HID's; From 250w-1000w. lw

  10. #9
    Garden Knowm's Avatar
    Garden Knowm is offline Registered+
    Join Date
    Dec-20-2004
    Posts
    5,835
    Quote Originally Posted by latewood
    I would like to add, A little stretching is not always a bad thing. I have found that If I want to grow plants lower in stature. then by stretching them a little, you allow more light penetration to the lower budsights. This is a matter of opinion, but I have a 400w MH for seedling/clone veg.
    How deep, south, asintx? Tx?

    GULP.... KNOWM FAINTS......


    : )

    taffy stretches
    a giraffes neck stretches to the highest branch..
    GARDEN KNOWM

    10 - 9 - 8 - 7 - 6 -5 - 4...

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •