Yellowing of new growth on seedlings 9 days old please help

so here it is:
3' x 3' tent
400 watt MH vented hood
temps are 80 at plant level with humidity around 40% during light hours and 65 degrees and 50 % during dark hours
plants are on a 20/4 light schedule and have been since they where a seed
light is 30 inches above them
plants are in a mixture of 8 quarts of ferti-lome seed and cutting mix, 2 cups of FFOF and 2 tablespoons of garden lime and are in 6" fibergrow pots
water is ph adjusted using ph down to 6.8 from 7.3 out of the tap. I let it sit out over night before feeding and i am not using any nutes.

As the title says i have some yellowing of new growth on one of my plants at the moment, the kicker is this is my 2nd attempt to grow since i set up the tent and the first time all 7 of my plants had this same yellowing and i ended starting over they got so bad. The first time around i did not have a PH meter and the plants where in straight FFOF and i believed i overwatered them. So for the 2nd go around i wanted to make sure i eliminated all the possible problems before i started and i though i had done so..... but yesterday the yellowing started. Another kicker is the first time i tried to grow in my tent my plants all begun to yellow around 8 days after sprouting.... and now this time its been 9 days.
So the question is what am i missing, or doing wrong?????
Hope someone can help so they dont all end up dying again
Thanks for your input!

They're fine man, you gotta stop the extra cal-mag (Dolomite) as it locks N and other elements when there's too much. Flush and then Feed at 1/4 strength.

My concern with what your saying is that i didnt use anything extra just straight FFOF my first go at this and i had the same issues so it seems to me like there is a common problem between my first attempt and this one. thanks for the reply bud!

I personally wouldnt use FFoF for such a young plant, as it is very hot. What are you watering with? I would guess MG deficiency for starters being yellowing of new growth. I think it's way too early to flush however, your plant looks pretty good, and I only flush as a last resort. With FFoF you're actually not supposed to add nutes the first month, which is why I stopped using that for my babies. I used to use FFOF for my rooted clones, and always had like 2 weeks of burned and stunted growth. I can't control the proper balance of nutes with a pre-nuted mix. I use a seed starter mix with extra perlite and manage the nutes myself after a week.

If you said you overwatered your first time around, that was probably the main issue, young girls are really suseptible to rot and such, and don't have the healthy root system yet to survive it. N deficiency is the most common for young babies, but like I said, my plants always took forever to start doing anything resembling healthy growth in FFOF. My friend does like to mix like 25% FFOF with Pro-Mix on his final transplant to 15 gallon pots. I don't think its bad, just too potent for a seedling. In any case I think you should be fine, using plain PHed water your girl will survive.

I am using a mixture of 8 quarts ferti-lome seed and cutting mix with only 2 cups of FFOF and then 2 tablespoons of garden lime to help keep ph in check. so if you use a seed starter mix with perite and have to add nutes after only one week then maybe i need to start adding nutes since i am in a seed starter mix as well?? I am watering with tap water that i PH down from 7.3 to 6.8 and i let it sit out overnight before using it as well.
Thanks

Another question, i am starting to see a few roots (not much) through the bottom of the fibergrow pots and wonder when i should repot into larger plants using straight FFOF soil and 3 or 5 gallon buckets?

Hoping for some more input everyone i am really stumped and want to keep these babies healthy!!!!

i think you have a slight nitrogen deficiency. a 1/4 feeding should help.does your soil have the time release nute balls?

should i feed just "N" or can i use the foxfarm grow big i have. Its 6-4-4. As for the soil, its a potting soil with what looks like no nute balls. I had some MG i used for some house plants that had the nute balls so i am pretty sure of what i am looking for and don't see any in this soil.
As for the "N" deficiency, doesn't "N" affect lower leaves first? Thanks for the help i am getting nervous!

I am having the same issue...except my yellow is more along the tips of leaves not so much in the middle...i dnt know if that makes a different...my starter soil has ur basic starter mix no nutes..i have redcently looked into the superwell bat guano and seen it may help? suggestions...im also using normal tap water that has sat out in open container over night..help plz!!

hey diesel your problem sounds like Mg nevertheless don't hijack the thread open one up!

Can anyone contribute some more help here???? I am new to this and really want to figure it out. When it happened to my first batch of plants i was reading non stop for a week trying to figure out the issue and could not. Even when i had decided they where beyond saving and i was gonna start fresh i still continued to find out exactly what my problem was so i could correct it this time around and hopefully not have the same problem. Not that the problem has returned and after i made many improvements i am stumped and figured my only chance is to start a thread with picture and get your guy's help.
let me hear what you experts think my problem is so i can move forward and not be so stressed out........

Bumpity bump

well the plant is looking worse today.... more yellowing and another is starting to yellow now as well. Gonna try and water with 1/4 strength nutes tonight.

supersuby said:

well the plant is looking worse today.... more yellowing and another is starting to yellow now as well. Gonna try and water with 1/4 strength nutes tonight.

Click to expand...

looks like they might be needing more of a rest try 18/6

I can try that..... messed up thing is i did try reducing light hours on my last run and it didn't help. But its worth a shot!
Thanks!

So here is an update, Hopefully some of you have some more input
On sat night a watered with quarter dose of Fox Farm's Grow Big as someone requested and the problem has changed but i am not sure if its worse or not lol Here are some pics, please compare with the originals and let me know what ya think.....

Thanks!!

No i have not..... i did add garden lime. 1 TBS per gallon of soil. Whats your thought??

Lol it's the same good job Happy growing