New hooks and 400-watt HPS

I just started putting some new hooks/seedlings under my 400-watt HPS.  It appears that after 1 day, a few of them are slightly curled at the edges.  So, I moved them to the perimeter of the grow area, for now.  Is this simply too much light for them, at this stage?  Should I put them back under the T8s for awhile, or can I just keep them at the perimeter of my grow area, which is 4x4?  I raised the HPS to 24-28" away.  Thanks.
 
IF you sprouted them under fluorescent for a week or two and then put them under the HPS, then Yes, it can curl the leaves a little. That is a bright light after all, but the little guys need to get used to it sooner or later. Put them at the perimeter for a day and move them closer the next day. A little bit of scorching on the cots won't really hurt the plant.
 
Yea, if you started under something other than the HiD, you can get the curling and possible frying. If the seeds sprout in sun, then they can handle the sun, but if they sprout under flouros, they will have a tough time adjusting so young. Also, if you have it available, you should be using a MH not a HPS. The HPS is for flowering and isn't going to hit the same spectrum as the veg MH bulb. I have lost a couple hundred starts over a month or so trying to figure out my MH. I use T5s for sprout and young growth now, and if they are in the tent long enough I will swap to the stronger MH.
 
I understand the disagreement, but from my experience I have to agree with mgold on this one. I have two 600W HID lights and both are running Hortilux MH bulbs. I have two Hortilux HPS bulbs but the plants didn't respond as well to them so I they're back on the shelf until the need arises. I noticed slower rates of growth and my plants weren't as bushy as they are under the MH. I know that defies all pepper logic but in my case I'll never use a HPS bulb for new or growing plants.

My sprouts stay under a T5 system until they have 2 sets of true leaves, then they're slowly introduced to the MH light. I place them on the outside edges for half of the time (7 hours) during the first 3 days, then they go for a full cycle. After about one week I start to move them in until they're completely saturated with light. It's a lot of work but I haven't had any trouble with burning leaves or shocked plants.
 
Also keep in mind that HPS puts out about 30% more lumens than MH, so you are broadcasting even more lumens than others in this thread.
 
Just speaking for 600 watts, since that is what I have experience with: A MH bulb is about 60,000 lumens and a HPS is about 90,000.
 
I use MH. It is plenty for my room and I like the spectrum better. Easier on the eyes.
 
Cayennemist said:
What is the "basking temp" Temp under the lamp?
 
I don't have a thermometer at plant level, but the back of my hand detects almost no heat from the bulb. The bulb is at least 24" away from the center plants.  Smallest plants are not directly under the light.  I do have a small fan running.  System runs 18/6.  I didn't realize with the older plants that had been under T8s, that they needed to be gradually introduced to the HPS.  No harm done that I can see.  As for the 2-3 day old sprouts, no more curling, although one Fresno may be on the way out.  Not bad for over 60 seedlings.  I'm keeping a close eye on them.
 
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