Safe light distance for seedlings?

[c2603976]

What would be a safe distance to keep seedlings at under a 400W HPS?
I've read that 1.5 ft. is safe, however the book didn't indicate if it's for seedlings or mature plants.

 

[straincreation]

Imo thatd way to close I say try 4ft at first and as they pop, inch the light closer and keep an eye on them. Or get a a t5 and start um ynder that.
Happy farmin:)

 

[soserthc1]

You would be much better off with just a common cfl close to the top of the seedlings to prevent them from stretching like crazy , then after they have stablished themselves and have 2 sets of true leaves introduce the 400 at a distance for a few hours each day and gradually more till there plants . That's the low budget way or just grab a t5 set

 

[budboy299]

Quite possibly I have been doing it all wrong but for years I started my seeds right under a 400w HPS from before they even broke the mediums surface. Never had any problems so far. Big BUT...coming up... If you do this you seriously must watch constantly so the soil/coco etc does not dry out. otherwise you will have a cooked seedling. You gotta figure that in nature the sun beats on the little buggers from as soon as they poke their heads above soil. I have actually had more problems with starting seedlings under lesser light and then trying to harden them off later on.
I think both ways are correct just either way there is due diligence required

 

[budboy299]

hmmmm further thought... I don't know what you mean by seedling. Just poking its head up? or ... already up and now you want to put a strong light on them? What kind of seedling do you mean? already hatched or baby plant?

 

[zombie III]

you really had no issues with an hps right above the seedlings??

 

[cephalopoda]

i agree, stick 2 cfls 2 start with. cheaper and with no problems..

 

[budboy299]

Nope had no problems. I only did this as I already had some clones I just put under the light and wanted to make use of the already running light instead of adding more. Seeds are only in the soil about 1/4" so it does not take long for 1/4" to dry out...thats why I said you have to be super diligent about watching the soil staying moist. I kept the new seed starts off to the outer edges of the light so as not to be too warm but once they poked their heads up and were about an inch high I moved them inward towards the light. I had far less stretching and way stronger main stems as well. CFLs or T5s are pretty much foolproof and best to go with them, but HPS can and has been done by me.

 

[motz]

Get rid of that hps for seedlings,use for flowering only. Flouros baby,flouros.. Cheaper to run,better looking plants.Under hps they won't get that dark,lush green leaves. The flouros seem to keep them shorter and bushes them out more. They look healthier

 

[c2603976]

Imo thatd way to close I say try 4ft at first and as they pop, inch the light closer and keep an eye on them. Or get a a t5 and start um ynder that.
Happy farmin:)

At 4ft there isn't enough PAR for seedlings to grow, it's useless.

Quite possibly I have been doing it all wrong but for years I started my seeds right under a 400w HPS from before they even broke the mediums surface. Never had any problems so far. Big BUT...coming up... If you do this you seriously must watch constantly so the soil/coco etc does not dry out. otherwise you will have a cooked seedling. You gotta figure that in nature the sun beats on the little buggers from as soon as they poke their heads above soil. I have actually had more problems with starting seedlings under lesser light and then trying to harden them off later on.
I think both ways are correct just either way there is due diligence required

There's nothing wrong with going with HPS from seed, the main reason people do MH/CFL is to provide a wider blue spectrum to encourage stem/leaf development. I've had problems with roots that are breaking off in peat moss cubes and stems collapsing while being transplanted into a 10l pot. Especially with anything Haze, damn that shit's fragile.

I've heard that 12" distance from seedlings is safe and it has ben done before.

 

[straincreation]

At 4ft there isn't enough PAR for seedlings to grow, it's useless.

There's nothing wrong with going with HPS from seed, the main reason people do MH/CFL is to provide a wider blue spectrum to encourage stem/leaf development. I've had problems with roots that are breaking off in peat moss cubes and stems collapsing while being transplanted into a 10l pot. Especially with anything Haze, damn that shit's fragile.

I've heard that 12" distance from seedlings is safe and it has ben done before.

Ok so 1st thing.
he said he wanted to start them off under hps wanted to jnow if it was ok. As bud boy said he did it, ive done it its possible. And to keep it safe I said try 4 ft and move them closer day by day when they pop. Par has nothing to do with seeds in the soil waiting to pop. After a day if they take well then move the light. Also depending on your genetics they will not like 12" hps light blasting them in the first days of life. Some might not like to much light at all. For instance I had a romulan cut that hated to much light. My canopy would yellow directly under the light. So theres that.

Ok so 2nd the IMO themain reason people use cfl/t5s is not only for blue spectrum. I run 3 blue one red in my hood. Its also to save on some energy. Keeping your plnts inches within the light i.e. Stops stretch. And save on cooling cost. Also to see how your strains are going to react to enviroment before blasting um with hps. So ya I would say to avoid going by claims and find out your self. Saying that you heard that 12" is ok doesnt mean it necessarily is. If you have done it then talk from experience.
Hapoy farmin;)

 

[Reuben JJ]

Never had an issue starting seeds under HPS from 1'-2'. Haven't gone closer...

 

[straincreation]

At 4ft there isn't enough PAR for seedlings to grow, it's useless.

There's nothing wrong with going with HPS from seed, the main reason people do MH/CFL is to provide a wider blue spectrum to encourage stem/leaf development. I've had problems with roots that are breaking off in peat moss cubes and stems collapsing while being transplanted into a 10l pot. Especially with anything Haze, damn that shit's fragile.

I've heard that 12" distance from seedlings is safe and it has ben done before.

Just realized that you posted those replys. Any ways one question why are you asking a question you alreadt know or aquired the info for.
Ok maybe you had found out after posting here but imo if you found it out why even reply. With a correction to might I add. I mean thats just me you ask for advice and then begin to spit knowledge on the subject???? Im perplexed.

Anyways happy farmin;)