Yellowing at the top/new growth on my seedlings

Discussion in 'Sick Plants and Problems' started by 50Dave, Mar 24, 2012.

  1. I am running 2 LED lights-one 135 watt and one 90 watt.

    I keep the lights about 16 inches away from the plants. Everytime I put them in the tent with this light, the top foilage gets yellow. Soil is Sunshine mix #4, runoff at 6.4, and inteneral temps of around 77-79.

    I can move the plants to seperate cfl based tent, and not have these problems. So weird. If anybody has any advice, by all means, chime in.
     

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  2. #2 1sttimegrower, Mar 25, 2012
    Last edited by a moderator: Mar 25, 2012
    off-gassing of it only happens in that tent. Usually happens due to higher temps with HID's - could be the direct light is exciting the material instead of heat.
     
  3. They are LED lights though. Temps are between 77-79 in there.

    The only thing other constant is the dolamite lime ive been using to sweeten up the soil since its been so damn acidic.
     
  4. I know they are LED - that's why I said the intensity of the light can be making the material gas instead of heat. Try throwing a CFL in there for a day instead of an LED?
    Or perhaps raise the LED's up - the intensity could be too strong for the plant itself. But it should bleech, not yellow..

    If you threw in too much lime that could be the issue... but I don't know. Never had a seedling yellow like that, except for when my plants were in my first and only tent under fluoros and if off-gassed and messed up my crop. a run-off of 6.4 sounds fine to me.

    Are you letting the soil dry? Any chance of fungal infection? It doesn't look like it, but I'm out of ideas personally - if the pH, lights, temps, watering are all good, I don't know.
     
  5. I moved that plant into another tent to see what happens. I also moved the one of my bigger veg plants into the tent withthe LED. Let's see what happens.
     
  6. I moved that plant into another tent to see what happens. I also moved the one of my bigger veg plants into the tent withthe LED. Let's see what happens. I also have another seedling that is showing the same signs as the other one. I am thinking I may need to get the seedlings started under cfl and then move them to the led after 2 weeks
     
  7. ^ Good ideas! Please report back what's going on - I want to try LED's once I get enough extra cash I can spend on lights, and dying seedlings would make me want to toss the LED right away haha
    Good luck man
     
  8. Ive grown/vegged several plants succesfully with the 90 watt triband UFO from HTG supply. When i got the second grow tent, i bought a 135watt UFO from htgsupply, and this is when I started having problems. After 1 and 1/2 day, ive started to see some yellow on a second seedling in the tent, just like the one pictured above. However, the plant i moved over from the cfl side of things seems to be doing fine. I would say I have my lights about 10/12 inches away from the plants right now. Im hoping thats enough. I never had my 90 watt ufo led farther away then that in other grows.

    I may end up buying a 4 foot/4 bulb t5 light set up if this doesnt work. Ill throw that 135 watt UFO in my flower tent for some side lighting to support my 400 watt HPS or something.
     

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