Hubby passed along some seeds to a newbie, wannabe grower and I believe I overdid it. Can you comment on whether I have too many plants per square in my trays (roughly 2)? If too many, what do you advise–thinning down to 1 plant, etc? Also, I have a VS200 Vivosun LED light roughly 18 inches from seedlings but given they are leggy, should I move the lighting closer? I live in the NE so have grow mats still under the trays as my tent is in the cold garage. Should I set up an oscillating fan? Your input is super appreciated!
Lower your light and bury the stems 
And Welcome to the clubhouse 
Welcome to the forum.
The stretching is due to inadequate lighting.
Your light is sufficient to flower 1 plant. I would pick the best seedling and get rid of the rest if you intend to grow under artificial lighting.
Thanks @MidwestGuy! I plan to transplant outdoors in early May. Does a 1.5 week seedling need 1 light? Or is it 1 200W light per adult plant?
1 bean per pot. They will fight for space and food and get intertwined at the rootzone.
Agreed on the leggy girls, need more light and don’t overwater them. Only a few ml at the perimeter when dry.
Seedlings don’t need as much light, but they do need enough to prevent stretching.
Correct if growing 1 plant. If you intend to grow more plants, then 45 watts per square foot of cannabis canopy is a good rule of thumb.
Hate to be the bearer of bad news, but that is 3 to 4 months away. You won’t be able to sustain a bunch of plants for that long with a single, 200 watt light.
Thanks! Do you believe I should nix the grow mats as I read that these can contribute to leggy seedlings also. I like in upstate NY so it’s freezing temps in my garage or am I good with the mats for now until summer?
I’d like to see where you read this. I don’t believe it to be true.
Mats can help if necessary. I wouldn’t let the soil get warmer than the upper 70s. Placing a towel between the mat and the seedlings can buffer the heat if it is too warm.
I keep my seedlings in a sprouter with dome for about the first 2 weeks. During this time, I leave my sprouter sitting on the heat mat with a towel between the mat and the sprouter tray.
Midwest stated this as well.
I vent the dome after the 3rd day and remove it a bit each day going forward. At 2 weeks, the dome is gone and I introduce a small fan and get my humidifier running at 60%.
The heat mat is under that towel
It gets pretty humid in there sometimes but at this age 80% is good.
Hope my info and pics helped a bit.
If using a humidity dome, then leave your soil completely dry until the dome is removed. The plant can get all of the water it needs via absorption of moisture through the leaves.
Avoiding overwatering is extremely important at this stage.
Thank you for clarifying the high RH and watering practices. I usually do not need to water while she is in the dome.
Welcome.
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Thanks everyone! This advice is helpful and a bit overwhelming at the same time as it appears that I jumped in with very little detailed knowledge. I took the dome off of my seedling tray the minute the first leaves emerged. I immediately then placed the tray in my 4 x4 grow tent under the grow lights 18 " above. I’ve since lowered the lights to 4" above with 20% dimmer. I don’t know if this is sufficient. My next steps are to repot to “bury” the seedlings. I also plan to whittle down the number of plants significantly to 4 
and purchase additional lighting. Any fertilizer tips at this time? Thanks for your patience.
Sounds like you are on the right track.
What soil are you using (brand and type?)
Welcome to the forum! I’m in Western NY and I think an early May outdoor transplant may be a bit ambitious. Happy Growing 
@soarhigher4 welcome to the ILGM forum.
Thanks again! I’m using Jiffy Organic Seed Starting Mix.
What soil will you be using for transplants? Soils have varying levels of nutes in them, delaying feeding requirements.
Oh, I’ve yet to purchase but if you have a recommendation, I’m totally open. Will be swinging by Home Depot this afternoon.