Switched lights... immediate leaf curling

[dirtbag]

The first pic is my garden at day 19 in veg under 48 Inch 6000K T-8 Full Spectrum Fluorescent Lamps. Everyone has taken off well for less than 2 weeks in dirt.
My problem happened when I moved them under my 400HPS with Hordilux bulb the tops of some began to droop an then the upper leaves curled inward. The light is about 24 inches away from the tops with fans blowing on the light and plants. The temps are 80 degrees at the top of the plants.
There's no way it's heat related. Could it be to much light? Should I go back to the floro's for the rest of the veg cycle or will this correct it's self with time?
My goal is to veg them as large as possible in the 5 week veg schedule I have them on. I figured they'd love the 400HPS but maybe not! The high intensity floro's seem to doing ok but I thought I could get more out of them with the 400HPS.
Given that this started within an hour of being moved under the HPS it's got to be a light issue. Any suggestions? Back to the floro's? Stay with the HPS and it'll improve?
Can't get the pics to post so I'll go ahead with this anyway and try and get the pics up later.

 

[sproutco]

Try having the fans blowing on the plants indirectly instead.

 

[dirtbag]

Finally figured that one out.
The first pic was yesterday right before I put them under the 400HPS.
The second pic is today.
The fan is indirectly blowing on them.
Absolutely no heat anywhere near the tops.

 

[sproutco]

Have you watered them lately? You should do that if you have not. Here is the lighting distance chart for hps:http://www.icmag.com/ic/gallery/showphoto.php?photo=150896&sort=1&cat=500&page=1

 

[mace_ecam]

upward curling leafes could be Mg or moisture stress related

it happened too fast for Mg imo, also i don't think that a 400HPS at 24 inches distance could create enough light for that kind of stress lol

so i'll guess moisture stress, can be created by a combonation of
- heat (also IR )
- low RH
- lots of wind

80 is to warm already, combined with wind and low RH...

do what sproutco suggested, whats your RH?

 

[dirtbag]

These plants have been in a constant temp of 80/82 degrees since they were put into dirt right after germination. I'm quite comfortable with that temp range. The growth speaks for it's self.
The PH is right on at 6.5.
Water isn't an issue either. This one was ready for water but the others that look exactly like this were watered early yesterday early.
I'm considering buying a MH conversion bulb for the 400HPS instead of using the Hordilux bulb. Possibly they prefer the stronger blue spectrum, but the Hordilux bulb is inhanced in the blue spectrum.
I'm at a loss on this one. I was under the impression that increasing light would be a plus. This is the first time I've ever started them under floro's and I'm quite impressed with the growth using these T8 bulbs. I just don't understand why they don't seem to like the HPS light.
As an experiment I watered the plant in the second pic, also first feeding(1/2 strength) and put it (Black Pearl) and one Hawaiian Snow, that looks the same, back under the floro's. Lets see what happens. The one thing I DON'T want to do is stress these plants any more than necessary. Hermies are not welcome for this grow!

 

[sproutco]

I don't know what your soil is but in soilless mixes containing peatmoss, perlite, etc... optimum ph is 5.6 to 6.2 See my signature for how to properly test ph and adjust your fert water ph after mixing. Raise the light even higher like its a cloudy day. They may just have to get used to the new light for a couple of days. This wont cause hermies.

 

[Guest]

dirtbag

Your leaves are folding up in response to the stronger light intensity. Move your light up a bit and you'll be fine. Plants look good otherwise.
Now, if it was me.........I'd pull them babies over LST style about now & get them side branches going.

Bh

 

[Verite]

dirtbag

Your leaves are folding up in response to the stronger light intensity. Move your light up a bit and you'll be fine. Plants look good otherwise.
Now, if it was me.........I'd pull them babies over LST style about now & get them side branches going.

Bh

Exactly, when something happens that fast in soil and its that specifically located you gotta figure its due to what you have done within the last 36-48 hours. Mist the dry stuff and move that light away.

 

[froth]

Yeah that will probably correct itself all on its own.. Same exact thing happened to my plants when I switched them from CFLs to a 250 HPS. Just get some good air flow in there and be patient.

 

[dirtbag]

It never occurred to me that the light would effect them that way but it makes since to me. Having never started with Floro's before I've never seen this particular problem before. I've been through most of the other problems associated with growing but not this one!!
I appreciate the help.

 

[Blackmelo]

those plants just weren't used to the new light.

When switching from something weak like fluoros to a hps you need to gradually make the plants used to the higher light intensity by starting high above the canopy and slowly lowering your light.

Most ppl keep their hps too close.

For seedlings you want a distance of 80cm (30 inches)

For small plants you want a distance of 60 cm (23 inches)

Beginning of flowering you want a distance of 40 cm ( 15 inches)

And depending on your cooling in flowering, you want the bulb as close as possible without burning the tops towards the end.

So you should have your hps at a distance of no closer than 80 cm or 30 inches at the stage they are at, especially since they just came from under fluoros, then every day lower by an inch or 2.

 

[MynameStitch]

yu p i concur, to much light to fast, move thel ight up a bit or put them abck under fluros untill they get used to the light when they get bigger
the leaves are curling over from intense heat and lumens
i would also get your grow temps under 80 F
hps is not the peroper spectrum for vegging plants and i have seen alot of plants get droopy or heat issues or to strong of a light for small plants like that

i have also found they grow much better in the proper spectrum and grow faster

the mh provides them with the blue spectrum which is what you want in vegging

and the hps orange color is what you want in floweing

if you combine them in flowering you get bushy and tall plants

 

[FrayedO]

I was about to ask the same question, only mine is unders a 1000 watt MH, so I know that the spectrum has nothing to do with it. It also happend with the 36 hours I switched them under the MH, my plants are just like his,just as big as his and everything. So that has to be because it is just them gettin use to the light.

 

[Erin Kerrik]

the mh provides them with the blue spectrum which is what you want in vegging

and the hps orange color is what you want in floweing

if you combine them in flowering you get bushy and tall plants

So combining them in flowering is good, but it's better to only use a MH for vegging? Ie, 1 400W HP in veg is better than using a 400W MH and 400W HPS?

 

[FrayedO]

No the more light the better but, 2 400 watt MH's are better then 1 400 watt MH and 1 400 watt HPS in veg. And same go's with HPS lights in flowering.