Hello I am brand new to the forum, this is my first post and my first ever grow, so forgive my ignorance. I am looking forward to this forum. On to my situation. This is day 8, pictured below. Day 1 being the day I dropped the seeds in water. I have a 2’x4’ tent with 4" ventilation and have a SF-2000 dimmed to 50% hanging 16" above the seedlings. I and doing the potforpot kits, so the seeds are in the jiffy pods. The temp ranges from 65 to 78 and RH has been ranging from 50-80. I bought a small cool mist humidifier I put in the tent to try to raise humidity before I read about the domes over them. I removed the cool mist humidifier and since last night have been using domes made of two liter plastic bottles with the lids still on and misting the inside of the bottle once last night and once this morning. Please advise me on the weird yellow leaf and white stuff on soil. Thank you in advance and excited to search years of posts for knowledge.
I would raise the light to 24-30”. The yellow tiny cotyledon is from minor nutrient burn and not uncommon. Keep the domes on and the count on days actually started when they broke ground. Dome for 10-12 days and I mist the inside of the dome so the leaves will absorb the water until the roots become stronger. Pot 4 pot medium will also feed them until around week 5 with PHd water only 
Welcome to the forum! Peat pods mold. Ive seen green/ brownish etc. They look fine. As a new parent you are hovering. Very common. I would get bottom temp up a touch. When you repot…cut the net and kinda gently loosen the peat. It will turn rock hard sometimes. The yellow leaf i wouldnt stress unless new growth shows stress. Now they are growing roots. If seem slow do not worry unless they droop or show signs of distress. When ready they will explode and surprise you. Just my thoughts. You can relax and letem do thier thing.
Welcome! Everything that was said above, plus if you can set your humidifier - 70 - 75% humidity is good for them, but try to keep them above 70, and less than 80 degrees.
Welcome, i agree with all above and would add a small fan to get a slight breeze going, it reduces mold conditions and plant stalks will strengthen
You’d raise the light even with it at 50%? I ask because one seems to be stretching. Thanks for the info!
You’d raise the light even with it at 50%? I ask because one seems to be stretching. Also you said dome for 10-12 days, but the two taller seedlings are showing a root coming out the bottom of the jiffy pod, and some other pods were saying to re-pot them when roots start showing. Today is only day 3 for them.
Thanks for the info!
Yes, what’s the wattage of the light. I typically use a T5 single 24” fluorescent light for the 1st week or so then they go under a 100 watt wills at 35% at 20”. I like seeing a little initial stretch, let’s me know to lower it, increase the intensity or both
Allinherhead,
I had a small fan going when I had the humidifier in there before using the dome, but it seems pointless when the domes are on, please correct me if I’m wrong.
That’s a good thing 
. What size pot are you going to use?
Do I need to remove the domes for an hour or two increasing the amount the dome is off each day until it’s off completely? For example dome is on 24 hours day one, 22 hours day two, 20 hours day three to allow time to expose the seedlings to a fan and breeze or do I just leave it on until the leaves touch the dome walls, just removing the dome to spray the mist and inspect the plant?
I remove the domes daily to mist and some air to circulate but nothing like you mentioned above
Yep, duh. Didnt see domes please forgive me
Pots are 5 gallon fabric. Will be using two 2’x4’ tents. Two plants in each tent. Light is 200 watts. I just was using the lights “recommended” height of 16"-22" and intensity of 50%. I initially had them at 22" but lowered them to 16". I’ll move them up to 25" and go from there. It made me wait before I could post again since I’m a new member.