Help with 400 watt distance from sprouts

I am have started to grow my seedlings under a 400 watt MH. The question that i have is that i dont know how far to keep the light away from the seedlings without burning them. But i also dont want them to stretch to bad. I dont have really any money so i cannot go for the cfl startup and then switch to the 400 watt. I know that this may not be the ideal way to grow the seedlings but its all ive got. So any feedback would be most appriciated!

For babies you want the light pretty much all the way up. With mature plants, 2 ft.

you need cfls to get light close, having your 400 all the way up is going to cause them to stretch.

Bro depending on ur lighting fixture if its air cooled or not..If it is air cooled u can be 18-24 inches away for seedlings and flowering 10-14inches...Rule of thumb if its hot on the back of ur hand its to hot for the plants...I have a 600w only 6 inches from the tops of a budding plant some have been burned tho but i cant do much about it and the plant isnt bitching to much...If it isnt air cooled add 4-6inches...JMO hope it helps GL bro.....

I have seedlings under a 400 watt right now. They were stretching under the CFLs so I put them under the MH early. I would say I have the light about 2 ft above the seedlings - they aren't stretching or burning. Very happy.

from my experience, if you are dealing with seedlings (from seed), its more about the heat that causes issues, rather than the intensity from a light that is too close... (a distance within reason; I mean you cant put an air cooled 600 or 1000 only 3-4" away)

When the seedling first breaks soil, it will pretty much adjust to whatever light is being used:

example: if you throw a seed outside, it will be ok with the intense, direct light from the sun, and grow great all the way through. However If you start seeds under cfl's, they adjust and get used to the low intensity light, right from the get go. Thats why when you go from cfl to straight outside, or from Cfl to straight under 600 or 1000 lights, sometimes the bleach, or are shocked becasue they are not used to that much light....

in theese cases you would need to put the light higher and slowly lower it untill you have a balance between the distance of light to plant, and amount of heat that is at the top of your plant....u want it as close as possible without burning crisping ( too much heat) or bleaching ( light intensity too much) the leaves...

I have started seeds under my 1000 HPS and MH (it is air cooled) and I put it about 18- 20" above the seedsings. And if my lights were not air cooled, my plants would fry because its sooooo hot, not because its too much light.

And also, from my experience, clones is another story...

Usually clones shouldn't be put under 600 or 1000 lights at close distances, because most clones are relatively "new" they dont have good enough root structures to handle the intensity at close distances. But after a weeks or two under the lights, I can lower to about 18- 20" (air cooled hood)

Thanks for all the input guys. I was actually thinking that I should go get some cfl and starting them in that since I wouldn't have to worry about the heat and everything. How many cfl per seedling?

Could you tell me how many cfls per seedling. I just would to see them grown spittle bigger before putting them under the 400 watt. I'm just scared that I will burn them.

You only need 1 23 watt bulb per seedling. Put it about 2 inches away from the plant.

Thanks guys for the quick feedback. Much appreciated. It's a htg 400 watt MH conversion bulb. And it's about 18 inches away. On the back of my hand at 18 inches isn't that hot. But I keep reading people say that it needs to be 2 feet away. That's why I'm scared of burning them. plus this is my first indoor grow. Also if my ant does stretch some in the beginning can I fill soil back around it? Kinda like backfill around it till the plant looks like it hasn't stretched that much?

Yes you can!
https://www.rollitup.org/newbie-central/429767-replant-those-long-stretchy-stems.html

I also go by my old book, they said for a 400 watt system it should be 2 feet away. So I measured down the fixture and added 2 feet, put my thermometer on the end and hung it up. Great way to tell the temp and make sure your plant isn't too close.

I veg all my plants with a 250w hps lol. Even my seedlings go under it lol. The back of the hand method is a good one, get a fan on em too, itll make em stronger and keep em cool.

if my hand feels cool at 18 inches should i leave the light there? Ive also put some sandwich baggies over the cups with tiny holes poked in the top to create a more humid environment for them. Do you guys think this is a good idea?

get a small twoo foot two bulb t5 its small so it will fit in top of your clone dome

I dont have really any more money to buy a t5. I spent all my money on the 400 watt and the materials and the seeds.

You can do it from seed to harvest with a 400w with no problems, you just have to get the environment correct.