Hi Guys!
I am new to growing and facing a problem with my “northern lights”: My leaves seem to turn yellow to white in an very early stage (week 2) of every grow I started so far. Is it light burn?
I am growing indoors in some sort of space a space bucket using a LED light (150W).
Distance to plant: 15inch (38cm).
Light shedule 16/8.
Soil should be fine, temperature is steady, two usb-fans do their job fine and I am careful with watering.
Any ideas on what I am doing wrong?
Best!
N
soil temperature is steady, at what temperature?
how big is the pots they are in?
as far a light burn, put your hand there if it is too hot for your hand it is
too hot for your plant
what kinda of soil? any nutes in it?
just asking questions to maybe help
thanks
Dequilo
hey @dequilo , thanks for your reply and help!
to be honest i do not check the soil temperature. Air temperature is around 68F (20C).
The pot has a diameter of 12 inch (30centimeters), soil is around 4 inch deep. To me it looks like it is pretty big…
The LED isn’t hot at all.
I am using some ready made soil:
Peat, perlite, worm castings.
pH (EN13037): 5.9 - 7.2
E.C. (1:1,5): 1.0 - 1.5 mS/cm
Prefertilised with 1,8 kg/m³ mineral fertiliser (NPK 12-14-24)
No extra nutritients so far.
thanks!
N
i hadn’t seen this in such a young sprout before, so i looked it up quick. it’s a bit more info than i’d like to type, but i hope this helps:
the air at 68 the soil maybe colder, feel it and you will know better if it is cold
12-14-24 might be a bit much for seedlings
12 inch pot even only 4 inches deep is a bit big for little plants
I have mine in 2 inch by 2 inch and 2 inches tall pots until they go to solo cups
look like to me they might be a bit wet and cold on the roots
just a guess 
tell me more
Dequilo
thanks for the link @kuntrybudz
true, the soil feels kind of cold, and its not dry at all. but I watered this morning, so i guess it is okay to be kind of moist right now… well, maybe I gave to much… hard to tell. Too much fertiliser? Well, screw you “Plagron grow mix”
The temperature confuses me a little. This “northern light” is supposed to grow very well outdoors in the north european summer. In this region air temperature can be under 68F for weeks. So my guess would be that the temperature should be fine. Or is mother earth warmer than my indoor pot? 
68 is fine but the soil may not be the air temp
grow well in the summer is one thing if you are a plant
a seedling in a big pot full of cold wet soil is another thing all together
you want to slow plants down keep them in cold soil, that is why it is always good
to get them off the floor in the winter
all the best
Dequilo
well, true… if you put it like that, it sure makes a huge difference
thanks for your time and help 
I will try to give even less water and find a solution for the heat situation!
From what i read so far, you are using fertilizer way to hot for a seedling. You should’t need to fertilize for a good week at all. And after that only very week solution for the next week 1/8th to 1/4 strength. And soil temps should always be colder than air temp. When I water the water temp is around 62 degrees, and my grow room is at 78-80 degrees. 4" is way too shallow for anything other than a very small seedling, your roots will spread out horizontially when they hit the bottom and make transplanting a pain. Current pot diameter is ok, but not the debth to diameter ratio. I remember being shocked at how long the tap root was the first time I used a cloner to start seeds with small grow baskets. At just two sets of leaves the root was a good two to three foot long. I started the seeds in a cloner because I wanted it to be completely soilless going into a RDWC system.
HTH
Marty
Alright, thanks Marty for your opinion and thoughts!
So I need to get some less prefertilised soil for my next seedling, let it grow for a week or two and then transplant it into my bucket, but with more soil. And also push the temperature…
I once read that auto flowers don’t like to be transplanted at all, so I thought I was doing the right thing by planting it right into the “final” soil … 
A lot of people do recommend starting auto flowers in their final pot because they have such a short growth cycle. What you could do is just get some Pete pucks. Fill your pot with soil just like you did soak the pete puck it will swell up then dig a hole in the middle of your pot peel the nylon mesh off of the Pete Puck and put it in the hole in your pot and then plant your seed in that. The seed has enough nutrients within itself to get the plant going so it will route in the Pete and then grow into the fertile soil. That soil is a bit hot for starting seeds this Will remedy your problem.
Oh yeah I always start my seedlings around 78°.
Oh yeah give your little seedling time. It’s probably going to shock if it doesn’t die so that will stall it for a little while if it survives
I use a dixie cup with about 3" of pure worm castings on the top and the bottom pure coco no additives, the worm castings have lots of stuff they like and won’t burn them. Then I let them grow until a few days after I see roots coming out the holes in the cup at the bottom, generally that gives them enough time to make enough roots to hold the soil all together, then when I get ready to transplant into the final pot, yes I transplant autos…I take another Dixie cup and use it to make a hole in the final pot, then I water the cup and let it sit for about 4 hours so it is good and moist but not wet, then gently squeeze the cup while it is upside down holding my fingers over the top to keep the soil from falling out, and then slide the cup off and tip it into the hole, all in one piece then push the coco firmly around it. The more you do it the eaiser it gets without screwing it up, and yes I have screwed them up lol. Anyway put a good innoculant in the sides and bottom of the hole before putting your seedling in. And don’t add any fertilizer for the next week until they get about 4 sets of leaves, then start with a gentle fertilization, always eaiser to correct not enough than too much. That is just how I do it, lots of different ways. I have grown autos with and without transplanting them and have never seen a difference. Even if it shocks them a bit it only lasts for two or three days. I use a minimum of a 3 gal pot.
HTH
Marty
thanks @happilyretired for your tips and sharing your knowledge!
Please explain… what is a Pete puck? I only found “Peter Puck”, an animated hockey puck that explained hockey rules to canadian viewers in the 70s
thanks @sssportsmfg for your advice!
24 hours later, some new photos and a little summary from what I learned so far (maybe for other beginners that struggle with the same issues):
Prefertilised soil not good for young seedling → start the seedling in unfertilised soil, then find a good way to transplant the seedling - even autoflower - into the final pot as soon as it has developed a good root structure (after 2-3 weeks).
Keep the pot away from cold ground → I raised it some inches. Now there is some space for air under the pot and hopefully it will raise soil temperature.
Looks like the problem is not light burn, also I don’t think that I over watered. Because 24 hours after my last watering the soil on top is almost dry. One inch deep it get’s a little moist, I guess that’s fine. Main reason for stress may be too much fertiliser.
Thanks for your help everybody! More ideas and tips are welcome
From here on out til she starts flower just use water and it should come back. Nutrients should not be needed for the first 4 to 6 weeks. Light at 16 inches might be a bit close also. Usually 18 is required but may be different for your light. Autos are super picky at the start but usually jump in pretty quick as long as u keep all the numbers in check.
Let me help get you dialed in bud…
What kind of soil are you using?
What kind of led light?(brand,rated wattage, and at wall wattage)
How often are you watering?
How old is the seedling?
What’s your pH? (Should be aiming for 6.2-6.5, other figured u posted is concerning)
So general rule of thumb when using liquid nutes is you do not want to give that seedling anything for around the first 7-10 days and since it an autoflower half strength as well.
That seedling is either dealing with nutrient lock out from a out of range ph or way to hot of a soil or a great combo of both. First noticeable lockout is usually iron and why the leaves are yellow having a lack of it. If it was a photo I would prob suggest correcting the issues and pushing forward but you have already lost precious time on the auto timer so ur at a crossroads of ditch the project and try again or try to salvage this. If planning to salvage it, I would very gently with a shower setting on low pressure get that seedling out of that soil without breaking any of the roots and get it into something less hot that it can stand a chance. If you can find the fox farms happy frog potting soil in your area then I’d run it entirely in that and ditch the nutes or do the fox farms ocean forest for the bottom 2/3 of your grow pot/bag and the happy frog in the top rest of it, that way the plant will be more established when the roots hit the hotter ocean forest soil in the bottom and can handle it
