My seedlings turn yellow and die off

[Minister]

Here´s my story: I´ve startet my launch of outdoor plants, as usual this year, at the end of March, with 100 danish climate acustomed seeds. All but 15 yellowed at the second/third pair of leaves, got stunted, developed poorly and had little or no root development. The set up was dirt,400 w hps 18 hrs. I figured the lights were to blame and unscrewed the bulb noticing cracks at it´s metal base.Then I invested in a 600 w mh ballast + bulb and crossed my fingers. Nothing got any better. PH had to be the problem, and sure the bags of dirt Iv´d used were from last year and had gotten sour 4,8 PH. Fortunately I had a shitload of durban seeds a couple of years old, and rushed to establish a new batch in soil with a PH of 6.
Today I´ve pulled my hair out, cause the problem seems to persist, allthough not with the mortality as noticed in the first try.
After searching in the infermery forum, the last couple of days my only conclusion is off gassing from the plastic sheeting i stapled to the plywood and/or th 90 l. plastic container supporting it. All platics got removed today. Two plants brought up in the window sill transformed into normal green color in a few days. Any suggestions? Could anyone link a picture upload guide? Tried but failed.

 

[ThcInfused]

your soil may be too 'hot' for the seedlings... consider a soil mix with minimal nutrients for the first few weeks. hope this helps !

 

[habeeb]

in the mini bar, go to user menu, then in the drop down go to my albums..

not sure if you need 50 posts first though?

 

[Minister]

Here comes the pics

Here comes the pics

Thanks to both of you, still I havent seen anything like it and imo I´ve done what I allways do.

1. The grow room 0.85x3.50
2. plants showing symptoms of yellowing from the inside out.

 

[Stress_test]

I think you are just killing em with intense light. I mean I use Cfl's with 100% on seelings. I know that clones turn yellow like that if they are under direct bright light before they have a few roots started and developed so they can feed the leaves. Try a few under a cfl and see what they do. Either that or try and shade em, so they get indirect light.

 

[PuReKnOwLeDgE]

^I have 100% success starting seedlings under 1000's, the sun is much more powerful then my 1000 watt light. The light actually looks pretty far away Bad soil mic or off gassing.

 

[Minister]

Thanks, it seems the two of you have a dispute in regards to light intensity just as in the infermary post from minejumper. He has similar symptoms with vegetative stage, well developed plants. Also, his plants seem to recover, when removed to the balcony. As for now there is certainly no plastics or fumes left so tonight I will install 4x33 w flourescents 6500 kelvin, and hope they can cover the room.
If this does not help it can only be bad soil.
There is 1 meter plus from bulb to seedlings.

 

[Minister]

Change of plan

Change of plan

Allright, this is what I did. Last year seedlings were actually sprouted under flourescents before they were moved to 400 w hps. How could I forget. Now I taped up a shade inspired by Mr stresstest and validated by the use of shadow paste painted on the inside of greenhouses during hot summer months.
Hope this works and they are not too stunted. the clock is realy ticking against me.

 

[ItGrows]

The yellowing from the inside out seems like a deficiency. Seems like a ph of 6 in soil is too low.

 

[Stress_test]

I agree that a 1000w Mh is less intense that the sun and all that. No debate from me at all there.
However, in my experience seedlings do far better and have more growth outdoors on lightly overcast days, when there sun is visible but behind a thin layer of clouds.

 

[Dave Coulier]

Minister, get rid of the shade cloth and move your light closer. Its too far away. It looks to be at least 5 feet above your seedlings. At that height they are not getting enough light.

I noticed the tall stretchy older plants in the back, and all the sticks in each container. You shouldn't need sticks to keep your plants upright. Drop the light to 3 feet above them, and I think you'll see an improvement.

 

[KanadianKronik]

ill agree with Dave Coulier.. your light is really high bring it down as far as you can so that all plants get light and no heat is reaching them.. you have to remember that the lumenents or what ever they are called can only make it so far before they are barely there. i do agree that its nice to start seeds and clones under t5's or cfl's but it is still 100% possible to do it with a hps or mh... i think i seen somewhere for dirt the ph should be between 6.4 to 6.6 im not sure tho so maybe look that up. maybe try some seed starting soil... or anything with nothing added as seeds dont need any nuts for a while.. take care and i wish all the best for your lil fellers
-KK