Light distance for seedlings

[asintx]

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 Reviewed by asintx on 04-23-2006. 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. Rating: 5

[latewood]

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

[asintx]

Thanks, Latewood, for the excellent information!

[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?

[asintx]

Yup, south TX.

[latewood]

I grew up in San Angelo...

[krustythfreakinclown]

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!

[latewood]

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

[Garden Knowm]

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..